Vertebral Body Trabecular Density at the Thoracolumbar Junction Using Quantitative Computed Tomography

Quantitative computed tomography was used to assess vertebral trabecular density in 26 post-mortem spines from individuals aged between 14 and 80 years. All vertebrae from T10 to L1 were scanned transversely near the mid-vertebral level with calculations of trabecular density in HUs averaged and referenced to a mineral equivalent phantom. An age-related decline in trabecular density was recorded (r = 0.55, p < 0.0001). Density measures from the anterior aspect of the vertebral body were significantly greater than from postero-lateral regions. From T10 to L1, there was a significant decrease in trabecular density, whereas density measures multiplied by vertebral body cross-sectional area were constant. Predictions of vertebral compressive strength using quantitative computed tomography may become more accurate by increasing the sampling area per scan and including vertebral body cross-sectional area as part of the radiologic assessment.

Low back pain misdiagnosis or missed diagnosis: Core principles

Consensus guidelines for the management of low back pain recommend that the clinician use contemporary best practice for assessment and treatment, consider biopsychosocial factors and, if chronic, use a multimodal and multi-disciplinary approach. Where guidelines are not followed and basic assessment is inadequate the diagnosis may be compromised and the sequelae of errors compounded. Factors such as a lack of knowledge or recognition of the common structure specific pain referral patterns, poor clinical reasoning, inappropriate referral and predilection for popular management approaches also contribute to mis-diagnosis and mis-management. This report describes two cases of chronic low back pain with lengthy histories of multiple failed interventions to highlight the consequences of focussing on a singular approach to the exclusion of evidence based pathways and the resulting risk of a missed diagnosis. The eventual management to mitigate these problems is reported with the aid of low back pain outcome measures, computer-aided combined movement examination, disability and pain questionnaires and health quality of life surveys.

Assessing the clinical utility of combined movement examination in symptomatic degenerative lumbar spondylosis

OBJECTIVES

The aim of this study is to report the development and validation of a low back computer-aided combined movement examination protocol in normal individuals and record treatment outcomes of cases with symptomatic degenerative lumbar spondylosis.

DESIGN

Test-retest, following intervention.

BACKGROUND

Self-report assessments and combined movement examination were used to record composite spinal motion, before and following neurosurgical and pain medicine interventions.

METHODS

151 normal individuals aged from 20 years to 69 years were assessed using combined movement examination between L1 and S1 spinal levels to establish a reference range. Cases with degenerative low back pain and sciatica were assessed before and after therapeutic interventions with combined movement examination and a battery of self-report pain and disability questionnaires. Change scores for combined movement examination and all outcome measures were derived.

FINDINGS

Computer-aided combined movement examination validation and intraclass correlation coefficient with 95% confidence interval and least significant change scores indicated acceptable reliability of combined movement examination when recording lumbar movement in normal subjects. In both clinical cases lumbar spine movement restrictions corresponded with self-report scores for pain and disability. Post-intervention outcomes all showed significant improvement, particularly in the most restricted combined movement examination direction.

INTERPRETATION

This study provides normative reference data for combined movement examination that may inform future clinical studies of the technique as a convenient objective surrogate for important clinical outcomes in lumbar degenerative spondylosis. It can be used with good reliability, may be well tolerated by individuals in pain and appears to change in concert with validated measures of lumbar spinal pain, functional limitation and quality of life.

Computer-aided combined movement examination of the lumbar spine and manual therapy implications: Case report

Combined movement examination (CME) of the lumbar spine has been recommended for clinical examination as it confers information about mechanical pain patterns. However, little quantitative study has been undertaken to validate its use in manual therapy practice. This study used computer aided CME to develop a normal reference range, and to guide provisional diagnosis and management. Two cases were assessed, before and after manual therapy using CME, a pain Visual Analogue Scale, the Roland Morris Low Back Pain and Disability Questionnaire and the Short Form (SF-12) Health Survey. Diagnosis and management were guided by comparing each CME pattern with the age and gender matched reference range. Self-reports data and CME total change scores were markedly improved for both cases, particularly for the most painful and restricted CME directions. This report describes how computer-aided CME and a normal reference range may be used objectively to inform a diagnosis and as an outcome measure in cases of mechanical LBP. Future investigations of cases with specific lumbar pathologies are required to validate this concept.

Referrer and service provider beliefs and attitudes towards rehabilitation in the home; factors related to utilisation of Early Supported Discharge

PURPOSE

To investigate the attitudes and beliefs held by referrers and service providers of an Australian Early Supported Discharge (ESD) service called "Rehabilitation in the Home" (RITH); with particular consideration of factors that may influence referral to RITH.

METHODS

A cross-sectional online survey based on the Theory of Planned Behaviour was undertaken.

RESULTS

There were 113 respondents; 90 referrers and 23 service providers. Referrers and RITH staff had a moderately favourable attitude towards RITH. The majority of referrers, and, to a greater degree, RITH staff members, understood and appreciated the advantages ascribed to ESD. However, views varied with regard to some of the factors upon which the decision to refer to RITH rests. Two-fifths of referrers did not think that RITH provided hospital equivalent therapy intensity and over one-fifth of referrers had concerns about the capability of the RITH service to provide specialist stroke rehabilitation. Opinion of RITH staff was also varied on these topics.

CONCLUSIONS

This study provides evidence that there was a level of uncertainty amongst referrers and RITH service providers regarding issues directly and indirectly related to patient eligibility and RITH service capability. This uncertainty needs to be explored in future research.

IMPLICATIONS FOR REHABILITATION

Differences in views held by referrers and ESD service providers were identified in this study that could lead to inconsistencies in patient selection for, and under-utilization of, ESD services. Improved communication between referrers and ESD service providers, for instance attendance of RITH staff at inpatient team meetings, could ameliorate some of these misconceptions. On-going education of referrers about service capability is essential to ensure timely transfer of appropriate clients to ESD services.

AGE-INDEPENDENT CORRELATION OF OPTICALLY DETERMINED THORACIC KYPHOSIS WITH LUMBAR SPINE BONE MINERAL DENSITY

The thoracic spine is susceptible to age-related increases in the sagittal curve, a process which is accentuated in osteoporosis. Previous studies have demonstrated an association between low vertebral bone mineral density (BMD) and accentuation of kyphosis. However, concerns of ionizing radiation associated with radiographic evaluation of osteoporotic fracture risks create a demand for alternative noninvasive detection methods. Back shape, and in particular the thoracic kyphosis, may act as a surrogate for bone density and complement methods of screening individuals for osteoporosis or monitoring progression. The aim of this prospective study is to establish the statistical association of mean lumbar spine BMD and the age-independent BMD Z-score with kyphosis, measured from noninvasive, rasterstereographic analysis of back shape. Back shape imaging of 42 females was performed following routine lumbar bone densitometry using dual energy X-ray absorptiometry. Kyphosis parameters derived from an optical back shape imaging system were correlated, using simple linear regression models, against mean lumbar BMD and BMD Z-scores. Moderate associations were noted between lumbar BMD and thoracic kyphosis (r=0.63 to 0.71, p<0.0001). The trend was still evident when correlating kyphosis against BMD Z-scores (r=0.57 to 0.68, p<0.0001). These data confirm earlier studies comparing radiographic indices of thoracic curvature with vertebral BMD, and suggest potential application of noninvasive back shape imaging to assist in the screening of individuals at risk of spinal osteoporosis, particularly in younger populations.

Non-surgical management of ankle contracture following acquired brain injury

BACKGROUND AND PURPOSE

The purpose of this study was to document the outcome of non-surgical management of equinovarus ankle contracture in a cohort of patients with acquired brain injury admitted to a specialist Neurosurgical Rehabilitation Unit.

METHODS

This prospective descriptive study examined all patients with a new diagnosis of moderate to severe acquired brain injury (Glasgow Coma Scale score </=12) admitted for rehabilitation over a 1 year period. Ankle dorsiflexion range and plantarflexor/invertor muscle activity were evaluated weekly during the period of hospitalization. Contracture was defined as maximal passive range of motion </= 0 degrees dorsiflexion, with the knee extended, on a minimum of two measurement occasions. Patients were retrospectively allocated to one of four treatment outcome categories according to ankle dorsiflexion range, type of intervention required and response to treatment.

RESULTS

Ankle contracture was identified in 40 of the 105 patients studied. Contracture resolved with a standard physiotherapy treatment programme, including prolonged weight-bearing stretches and motor re-education, in 23 patients. Contracture persisted or worsened in 17 of 40 cases, all of whom exhibited dystonic muscle overactivity producing sustained equinovarus posturing. Ten of 17 cases required serial plaster casting (+/- injection of botulinum toxin type A) in order to achieve a functional range of ankle motion. Remediation of ankle contracture was not considered a priority in the remaining seven patients due to the severity of their overall disability.

CONCLUSION

The incidence of ankle contracture identified in this population was considerably less than previously reported. Reduced dorsiflexion range was remediated with standard physiotherapy treatment in over half of the cases. Additional treatment with serial casting +/- botulinum toxin type-A injection was required to correct persistent or worsening contracture in one quarter of cases. Dystonic extensor muscle overactivity was a major contributor to persistent or progressive ankle contracture.

An open label pilot investigation of the efficacy of Botulinum toxin type A [Dysport] injection in the rehabilitation of chronic anterior knee pain

PURPOSE

To examine the effect of intramuscular injection of botulinum toxin type A [Dysport] to reduce relative overactivity of the vastus lateralis [VL] muscle, in conjunction with re-training of vastus medialis [VM] muscle as an adjunct to rehabilitation for chronic anterior knee pain.

METHOD

Eight females with chronic (>6 months) history of anterior knee pain, who had failed conservative management, were studied in this open label pilot study. Intramuscular Dysport injection [300 - 500 units] to the distal third of VL muscle was followed by a 12-week customized home exercise programme to improve recruitment of VM muscle and functional knee control. VL and VM muscle cross sectional area from a standardized spiral CT sequence, isometric quadriceps strength (dynamometry), timed stair task, self-reported pain and disability were assessed.

RESULTS

Subjects reported reduced knee pain and brace dependency and increased participation in sporting and daily living activities. Isometric quadriceps muscle strength was maintained or improved despite significant atrophy, evident on CT, of the distal component of VL in the treated limb. Time taken to ascend and descend a flight of stairs improved in all subjects. Subjective and objective improvements were maintained at 24-week follow-up.

CONCLUSIONS

These pilot data provide preliminary support for the role of Dysport as an adjunct to non-surgical management of individuals with chronic anterior knee pain. Larger double blind, randomized, placebo-injection controlled studies of this novel approach to improving patellofemoral mechanics are needed to establish the efficacy of this intervention.

The short term effect of cyclic passive stretching on plantarflexor resistive torque after acquired brain injury

BACKGROUND

Increased calf muscle stiffness is a common impairment following acquired brain injury. This study examined the immediate effects of cyclic ankle stretching at two stretch velocities on calf stiffness in individuals with hemiparesis (n=17) and control subjects (n=10).

METHODS

Cyclic ankle stretching was applied for 3min at velocities of 5 degrees s(-1) and 25 degrees s(-1) using a purpose-built dynamometer. Surface electromyography was employed to ensure stretches were passive. Peak plantarflexor resistive torque was derived from torque-angle curves. Comparisons were made between groups, velocities, and between limbs for hemiparetic subjects.

FINDINGS

At baseline, mean peak plantarflexor resistive torque was greater in the affected limbs of hemiparetic subjects than their contralateral limbs (P<0.001), however there was no significant difference between groups. Plantarflexor resistive torque was reduced in all limbs following cyclic stretching regardless of stretch velocity (P<0.005). Two distinct patterns of response were observed in hemiparetic subjects. In nine cases the affected limb responses did not differ from the contralateral limb or control data. In the remaining eight cases mean peak plantarflexor resistive torque in the affected limb was greater than the contralateral limb and control values. In this subgroup, peak plantarflexor resistive torque was significantly affected by stretch velocity and showed the greatest reduction following cyclic stretching.

INTERPRETATION

Cyclic stretching has been shown to produce a short term reduction in calf stiffness in a subgroup of individuals with hemiplegia. Further investigation is required to elaborate the characteristics of those most likely to respond optimally to this intervention.

Botulinum toxin injection to facilitate rehabilitation of muscle imbalance syndromes in sports medicine

Intramuscular injection of Botulinum toxin to produce reduction of focal muscle overactivity, and localized muscle spasm, has been utilized therapeutically for almost two decades. Muscle overactivity in neurologically normal muscle, where an imbalance exists between a relatively overactive muscle and its less active synergist or antagonist, can inhibit control of the antagonist producing a functional muscle imbalance. This brief review provides an overview of the role of muscle imbalance in sports-related pain and dysfunction, and outlines the potential for intramuscular injection of Botulinum toxin to be used as an adjunct to specific muscle re-education and functional rehabilitation in this patient group. A comprehensive understanding of normal movement and the requirements of the sporting activity are essential to allow accurate diagnosis of abnormal motor patterns and to re-educate more appropriate movement strategies. Therapeutic management of co-impairments may include stretching of tight soft tissues, specific re-education aimed at isolation of the non-dominant weak muscles and improvement in their activation, 'unlearning' of faulty motor patterns, and eventual progression onto functional exercises to anticipate gradual return to sporting activity. Intramuscular injection of Botulinum toxin, in carefully selected cases, provides short term reduction of focal muscle overactivity, and may facilitate activation of relatively 'inhibited' muscles and assist the restoration of more appropriate motor patterns.

Evaluation of extensibility, passive torque and stretch reflex responses in triceps surae muscles following serial casting to correct spastic equinovarus deformity

PRIMARY OBJECTIVE

Spastic equinovarus deformity of the ankle in adults with acquired brain injury can severely limit the achievement of rehabilitation goals. This study examined changes in triceps surae muscle extensibility, passive resistive torque and soleus stretch reflex responses in 10 adult brain injured subjects undergoing serial casting to correct ankle equinovarus deformity.

METHOD

Goniometric measurement of maximal passive dorsiflexion was used to evaluate extensibility of the triceps surae muscles. Computer controlled ankle dynamometry and surface electromyography were used to identify passive resistive torque and soleus stretch reflex onset angle in response to stretches at two velocities.

RESULTS

The mean casting period was 5 weeks. Casting was discontinued in one subject due to failure to achieve measurable gain in ankle range over three consecutive cast changes. Median improvements in maximal ankle dorsiflexion, with the knee flexed or extended, of 30 degrees and 15 degrees, respectively, were achieved in the remaining nine subjects (p < 0.0001). The median passive ankle range in response to a displacing torque of 10 Nm increased 4.3 degrees over the intervention period (p < 0.0001). Consistent soleus reflex activity in response to passive stretches at 25 degrees x s(-1) was elicited in only four subjects. A trend for the stretch reflex onset to move further into the available range was demonstrated in these subjects.

CONCLUSION

In the present study, serial casting contributed to significant change in triceps surae extensibility and passive resistive torque, corresponding with improved maximal passive ankle dorsiflexion range and an increase in the angle achieved with a displacing torque of 10 N.m. Increased stretch reflex threshold was observed in some subjects. The use of pre-determined outcome criteria and careful measurement of responses to this intervention were important to prevent premature discontinuation of casting when gains were slower than expected.

Velocity dependent passive plantarflexor resistive torque in patients with acquired brain injury

OBJECTIVES

This study sought to determine whether factors other than stretch reflex excitability contribute to velocity dependent passive plantarflexor resistive torque following brain injury.

BACKGROUND

In patients with acquired brain injury increased resistance to passive muscle lengthening commonly results from abnormal muscle contraction, secondary to disinhibition of descending motor pathways, in addition to rheologic changes within the musculo-tendinous unit. Hyper-excitable tonic stretch reflex responses (spasticity) have traditionally been considered to be the main factor influencing resistance that is velocity dependent.

METHODS

Ten adults with brain injury and eighteen age matched controls were studied. A computer controlled torque measurement system was utilised to evaluate resistance to dorsiflexion stretches at two velocities (5 degrees and 25 degrees s(-1)). Only stretches which did not evoke muscle contraction were included in the data analysis. The mean difference and 95% confidence limits in passive plantarflexor resistive torque at two stretch velocities, measured over a defined portion of the test movement, were compared between subject groups.

RESULTS

A velocity dependent increase in passive plantarflexor resistive torque was evident when the ankle was dorsiflexed past the neutral position in both subjects with brain injury and controls. However, the mean difference was approximately 10 times greater in neurologically impaired limbs compared with control values.

CONCLUSIONS

These data indicate that an important component of velocity dependent resistance to passive muscle lengthening in adults with brain injury can be mechanical, and unrelated to stretch induced reflex muscle contraction.

RELEVANCE

Increased resistive torque during rapid muscle lengthening may represent a compensatory adaptation for reduced distal motor control following brain injury. A velocity dependent increase in passive plantarflexor resistive torque has the potential to improve stability during gait and provide mechanical resistance to sudden external perturbations.

Evaluation of triceps surae muscle length and resistance to passive lengthening in patients with acquired brain injury

OBJECTIVE

To examine changes in muscle length and resistance to passive lengthening in the triceps surae muscles in patients with recently acquired brain injury.

BACKGROUND

Increased passive resistance in the triceps surae muscles is common following acquired brain injury. Adaptive shortening secondary to relative immobility, and increased stiffness due to rheologic changes within the musculo-tendinous unit, may be exacerbated by plantarflexor muscle overactivity related to the brain injury itself.

DESIGN

Three variables representing resistance to passive lengthening and soleus muscle length were compared between subjects with recent brain injury and age matched normal controls. Comparison between limbs was made for subjects with unilateral neurological impairment.

METHODS

Slow passive dorsiflexion stretches were performed using a computer controlled dynamometer. Muscle stiffness in the initial and latter portion of the range, and the angles achieved at torques of 5 and 10 N m were determined from torque-angle curves. Maximal ankle dorsiflexion with the knee flexed was considered to reflect soleus muscle length.

RESULTS

Significant differences were demonstrated for all variables, except passive stiffness near the end of available range. The limb ipsilateral to unilateral brain injury differed from control limbs in that significantly less passive range of dorsiflexion was available and initial resistance to passive stretch was significantly less.

CONCLUSIONS

The reduction in soleus muscle length evident in subjects with recent acquired brain injury, even in neurologically unaffected limbs, may reflect the influence of relative immobility. Although plantarflexor muscle overactivity was found to be associated with increased resistance to slow passive stretch, the mechanism was unable to be elucidated from these data. The limb ipsilateral to unilateral neurological impairment cannot be considered to be a 'normal' control for comparative purposes.

RELEVANCE

Adaptive shortening and increased resistance to passive lengthening limit active ankle dorsiflexion, and alter ankle biomechanics. Tonic muscle overactivity has the potential to exacerbate these changes. Prophylactic management of inappropriate muscle activity and maintenance of muscle length may facilitate the achievement of rehabilitation goals and reduce subsequent disability following acquired brain injury.

Serial plaster casting to correct equino-varus deformity of the ankle following acquired brain injury in adults

PURPOSE

Proposed mechanisms via which serial casting might effect increased joint range, muscle extensibility and reduced reflex excitability are outlined in this review. Support for these mechanisms stems largely from animal experimental studies. The applicability of these data to human muscle is unknown.

ISSUES

Equino-varus deformity of the ankle is a common secondary complication of acquired brain injury. It results from a combination of sequelae of the brain injury and subsequent immobility, including hypertonia, reduced muscle length and increased stiffness. Some evidence exists for the efficacy of serial plaster casts in the treatment of equino-varus deformity, although most reported studies are uncontrolled and involve small numbers of subjects. Serial casting has been shown to result in decreased resistance to passive lengthening and a reduction in dynamic reflex excitability within the lengthened muscles in children with cerebral palsy. Currently documented effects of serial casting in brain injured adults are limited to changes in range of maximal passive dorsiflexion.

CONCLUSION

Serial casting should be considered as an adjunct to therapy aimed at improving functional mobility. A variety of therapeutic interventions have been used to augment the effect of the casting regime. Factors that have been demonstrated to be associated with a favourable outcome from serial casting, and recommendations for future research are also discussed in this review.

MRI evaluation of lumbar spine flexion and extension in asymptomatic individuals

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.

Navigating the internet maze

The 'internet-driven information age' is a term in common usage, implying that everyone can access all the information they need, when they need it. The purpose of this brief paper is to outline some web sources that highlight the possibilities and potential for accessing web-based knowledge. From this the clinician will be encouraged to follow leads along the labyrinth of links to a greater appreciation of how this resource can be used to shape their practice. Examples of web links are provided for: search engines; library-based sources, including medical databases and electronic journals; evidence-based practice databases, mail-groups; electronic conferences; research centres; and general health sources. Importantly, this review does not aspire to be all-inclusive, for the web changes, chameleon-like, to the seasons. The web is here to stay. It will provide the framework for much education and will guide clients to a greater appreciation of their disease or disability than ever before. It may ultimately be the tool through which health fund agents will promote best practice, including self-help to clients, and therefore direct discriminating individuals to select health practitioners who have been endorsed by professional and fund agencies as providing a contemporary service which conforms to evidence-based practice.

Magnetic resonance-based vertebral morphometry of the thoracic spine: age, gender and level-specific influences

OBJECTIVE

The aim of this study was to examine age, gender, and segmental trends in thoracic vertebral body shape, utilising thoracic spine magnetic resonance images involving an age range spanning the life span.

DESIGN

A quantitative, cross-sectional, retrospective study design involving a sample of convenience.

BACKGROUND

Thoracic vertebral shape data are commonly derived from radiographic resources. The non-ionising properties of magnetic resonance imaging and availability of digital data for image analysis suggest potential for MR-based morphometric studies. For the thoracic spine, there is limited vertebral shape data on males, while few studies have examined the pattern of age-related changes across the life span.

METHODS

Morphometry was performed on 220 mid sagittal T1-weighted MR images using image analysis software. Three indices of vertebral shape were utilised: the antero-posterior height ratio or anterior wedge index, mid-posterior height ratio or biconcavity index, and ratio of posterior vertebral height to mid antero-posterior diameter or compression index.

RESULTS

Different segmental patterns were noted for the vertebral shape indices. Significantly lower mean values were noted in males for the compression index. Age trends were significant, with a linear age-related decline demonstrated for the anterior wedge and biconcavity indices, and a quadratic trend noted for the compression index.

CONCLUSIONS

Thoracic vertebral body shape may be uniquely described using specific shape indices, for examining various segmental, gender and age-associated changes.

RELEVANCE

These results suggest the importance of defining specific reference criteria for thoracic vertebral body shape indices, particularly age-related data encompassing a wide age range. Magnetic resonance studies enable interpretation of vertebral shape data in relation to the wide spectrum of pathologies afflicting the thoracic spine, without the concerns of ionising radiation.

Normal values of plantar pressure measurements determined using the EMED-SF system

Plantar pressure-measurement technology is being increasingly used by podiatric physicians and surgeons in both clinical practice and research. The authors present normal reference-range values for peak pressure, mean pressure, and pressure-time integral obtained from 30 healthy subjects using a two-step recording technique and the EMED-SF system, as background for proposed clinical trials. Normative data of this type are essential for clinical practice in the comparison of plantar pressure-measurement values of individual patients with those of normal, asymptomatic feet.

A comparison of three methods for measuring thoracic kyphosis: implications for clinical studies

OBJECTIVES

To compare the Cobb technique for measuring kyphosis with an alternative Cobb method and a computer-assisted curve assessment technique, and to examine the influence of vertebral body and disc shape on kyphosis.

METHODS

Kyphosis measurements were derived from 93 lateral spinal radiographs or sagittal computed tomography images of cadaveric spines, using: (i) a computer-assisted method for estimating radius of curvature; (ii) the traditional Cobb method; and (iii) an alternative Cobb method. Regression models were applied for agreement analyses, and to examine the relative contribution of vertebral body and disc shape on the extent of curvature. Results and conclusions. Strong associations existed between curvature and angle data derived from the three methods, confirming the clinical utility of these techniques for the quantification of thoracic kyphosis. However, the traditional Cobb method tended to overestimate kyphosis in the presence of vertebral body end-plate deformation. The degree of kyphosis was strongly reflective of the extent of deformity of the vertebral bodies, and to a lesser extent the shape of the thoracic discs.

The relative influence of vertebral body and intervertebral disc shape on thoracic kyphosis

OBJECTIVE

The aim of this study was to quantify the morphology or shape of thoracic vertebral bodies and intervertebral discs, and to examine the ex vivo association of thoracic kyphosis with these shape parameters.

DESIGN

A quantitative, retrospective study design was applied to define vertebral body and disc influences on thoracic kyphosis.

BACKGROUND

Age-related progression of thoracic kyphosis is a well-defined process that is influenced by the morphology of vertebral bodies. However, little is known about the contribution of intervertebral disc shape to the thoracic curvature.

METHODS

Vertebral and disc morphology, as represented by antero-posterior height ratios, were quantified in 93 lateral spine radiographs and midsagittal computed tomography films of ex vivo spines. Kyphosis was indicated by the Cobb angle. Linear and stepwise regression were applied to examine relationships for cumulative (T1-T12) and regional (T4-T9) analyses.

RESULTS

Vertebral morphology was highly predictive of thoracic curvature, while a poorer association was noted for disc morphology. The combined influence of both accounted for >85% of the variability in kyphosis. There was a trend for a more pronounced anterior wedge configuration of the midthoracic vertebral bodies and discs. Higher associations between variables were also noted in this region.

CONCLUSIONS

The normal kyphosis of the thoracic spine reflects the morphological adaptation of both the vertebral bodies and intervertebral discs.

RELEVANCE

This study contributes new data on the thoracic spine, particularly the characteristics of thoracic discs and their contribution to kyphosis genesis. Future directions for morphology studies should encompass more detailed examination of the thoracic discs and greater emphasis on the midthoracic segments, considering the prevalence of osteoporosis related fractures and subsequent deformity at these levels.

The effect of hallux valgus correction on chronic plantar ulceration. A case report

Plantar pressure-measurement technology may provide the clinician with valuable objective information for monitoring the effects of therapeutic intervention on the foot. The use of this technology is described in the preoperative and postoperative assessment of a patient undergoing hallux valgus surgery for the treatment of a chronic neuropathic skin ulcer over the medioplantar aspect of her first metatarsophalangeal joint.

Assessment of combined movements of the lumbar spine in asymptomatic and low back pain subjects using a three-dimensional electromagnetic tracking system

Combined movement examination (CME) is used by physiotherapists to assess and treat patients with low back pain (LBP). However, this method has not been subjected to quantitative assessment. The purpose of this study was to discover if CME of the lumbar spine could be measured with acceptable intra-examiner reliability and to make a preliminary investigation of the effect of LBP on the results of CME. Combined movement examination of the human thoracolumbar spine was measured using a three-dimensional electromagnetic goniometer (3SPACE Fastrak Polhemus, Colchester, Vermont, USA). 1. Intra-examiner reliability of CME was evaluated using a test-retest design; examination was repeated in 23 subjects without LBP and 16 with LBP. 2. A sample of 31 subjects without LBP and 23 subjects with LBP underwent CME, which involved measuring right and left sideflexion in the flexed, neutral and extended position. Pearson's r and the intraclass correlation coefficient for all variables ranged from 0.79 to 0.93 (P < 0.05). A MANOVA test (P < 0.05), comparing the combined effects of the two variables for each position, was used to test for a difference between the positions attained by the subjects with LBP and those without. Generally LBP subjects showed smaller ranges of movement than those without LBP. Each position was recorded as a degree of rotation around the x-axis (flexion/extension) and around the y-axis (left and right sideflexion). CME can be carried out with acceptable intra-examiner reliability; preliminary evidence is presented concerning the effectiveness of CME in identifying reduced spinal movement in LBP subjects.

Measurement of vertebral body heights: ex vivo comparisons between morphometric X-ray absorptiometry, morphometric radiography and direct measurements

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.

Review of radiographic measurements following Austin bunionectomy

This study compared preoperative and postoperative results for selected radiographic measurements of 30 patients undergoing the modified Austin bunionectomy procedure for the correction of hallux abducto valgus. Significant reductions in all postoperative radiographic values were demonstrated, including hallux abductus angle, metatarsus primus adductus angle, tibial sesamoid position, and first metatarsal protrusion distance.

Thoracic spine: anatomical and biomechanical considerations for manual therapy

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.

Assisted reach and transfers in individuals with tetraplegia: towards a solution

The purpose of this study was to investigate the influence of a prototype trunk orthosis to assist an individual with tetraplegia. A single case study (26 year old male, C5 motor complete) using an interrupted time series analysis was conducted to investigate the individual's ability to reach, forward and laterally, and transfer with and without the orthosis. All tasks were performed on an AMTI force platform in the long sitting position, with landmarks of the trunk and limbs recorded using Peak Performances Technologies motion analysis system. After a familiarisation period ten trials were attempted for each phase of the analysis. With the orthosis the subject altered the sitting posture and significantly (F = 9.55, P = 0.003) increased the distance the subject was able to reach. The median frequency of the centre of pressure (COP) displacement during the reaching task was not significantly altered. The ability to displace the COP when attempting to transfer increased from 16.0 (+/-3.4 cm) to 19.6 (+/-2.5 cm), however, this was not statistically significant. The likely user population, the overall functional benefits, the compliance of the users and possible modifications to the device to facilitate use with functional electrical stimulation are all possible directions for future research.

Ex vivo estimation of thoracolumbar vertebral body compressive strength: the relative contributions of bone densitometry and vertebral morphometry

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.

Morphological survey of the cervicothoracic junctional region

STUDY DESIGN

Vertebral morphology of the cervicothoracic junctional region was studied using the C6 to T4 vertebrae from 51 disarticulated skeletons (26 males and 25 females).

OBJECTIVES

Orientation of the facet joint pair relative to the plane of the superior endplate and the sagittal reference was recorded. A vertebral index was developed to compare the superior endplate surface area with the posterior vertebral body height.

SUMMARY OF BACKGROUND DATA

Vertebral morphometry was recorded for comparison with the limited published data for this region.

METHODS

The disc-facet angle was measured using a zygapophysial endplate protractor and the facet angle recorded from computer-aided digitizing of photographs of each segment. Vertebral dimensions were measured using Mitutoyo digital calipers.

RESULTS

A marked change in disc-facet angle from C6 to T1 was recorded, with the incidence of right versus left asymmetry highest at the T1 level. The incidence of facet angle asymmetry greater than 10 degrees was 24% at C6, 18% at C7, and 16% at T1. The vertebral index indicated no significant gender difference.

CONCLUSION

Consistent with other junctional regions of the spine, the cervicothoracic transition has significant morphological variations.

Transfer movement strategies of individuals with spinal cord injuries

The ability to transfer in tetraplegia is a focal point of rehabilitation. Many factors have been associated with independence in transferring, yet the majority of these are anecdotal reports. The purpose of this paper is to report preliminary findings of the study of movement strategies of individuals with spinal cord injury attempting a long sitting transfer. Analyses were made from the lateral and posterior views. Pattern recognition techniques show two distinct movement strategies in both views. These were a lift and forward flexion technique from the lateral perspective and a translatory and rotatory technique when viewed from behind. It would seem that the posterior view provides more discriminative information. It is recommended that intervention techniques, such as Functional Electrical Stimulation or orthotic devices be developed within fundamental motion analysis constructs to optimize functional outcome.

The effect of body position on bioelectrical resistance in individuals with spinal cord injury

The purpose of this study was to determine the effect of four different body positions on the resistance of the human body as assessed by Biodynamics Model 310 Body Composition Analyzer in a healthy population (Group A, n = 69) and long-term spinal cord injured (Group B, n = 13). Group A were tested in four body positions: supine, half-lying, standing and sitting in a wheelchair, while Group B were tested in supine and sitting positions. Testing order was randomized. A one-way repeated measures analysis of variance and a paired t-test demonstrated significant differences between position (p < 0.0001, Group A; p < 0.01, Group B respectively). In both groups, the greatest reduction in resistance was demonstrated for the sitting position. These differences were similar for both groups, as demonstrated by covariant analysis. Regression analysis demonstrated that supine resistance can be accurately predicted (R2 = 0.98) from assessments in a wheelchair. Such data transformations may be indicated where supine positioning is problematic or when wheelchair assessment procedures are more appropriate.

Segmental trends in cancellous bone structure in the thoracolumbar spine: histological and radiological comparisons

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.

The relationship between bone mineral density, vertebral body shape and spinal curvature in the elderly thoracolumbar spine: an in vitro study

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.

Computer-assisted curvature assessment and Cobb angle determination of the thoracic kyphosis. An in vivo and in vitro comparison

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.

Formalin fixation effects on vertebral bone density and failure mechanics: an in-vitro study of human and sheep vertebrae

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.

In-vitro relationships between vertebral body density, size, and compressive strength the elderly thoracolumbar spine

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.

Accuracy of lateral dual energy X-ray absorptiometry for the determination of bone mineral content in the thoracic and lumbar spine: an in vitro study

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.

Influence of zygapophyseal joint orientation on hyaline cartilage at the thoracolumbar junction

Hyaline articular cartilage from 102 thoracolumbar junction zygapophyseal joints was examined using light microscopy. One section from the upper, middle and lower third of each joint at the T10-11, T11-12, T12-L1 and L1-2 spinal levels was photographed using 35 mm color film. Hyaline articular cartilage cross-sectional area of the superior and inferior articular processes of each joint pair, at each level, was digitized using computer-aided planimetry. Differences in area were compared with joint orientation (symmetry or tropism) and geometry of each joint pair at each spinal level. Variation in hyaline cartilage cross-sectional area between joint pairs could be attributed to: a) geometric differences, b) the presence of a mortice joint, or c) osteoarthritic changes, with or without tropism. These findings were most frequently demonstrated at the transitional levels of T11-12 and T12-L1.

Accessory ossification centres at the thoracolumbar junction

A survey of 810 thoracolumbar junction CT scans demonstrated several forms of accessory ossification centres and vestigial ribs associated with the posterior element processes. Four examples of short T12 ribs and 15 L1 ribs were identified, in addition to 8 accessory ossification centres at L1, and 3 at T12. Radiographic features of accessory ossification centres were compared with histologic characteristics from cadaver studies. Accessory ossification centres have occasional clinical significance when they may be confused with fractures at the thoracolumbar junction. Differential diagnosis relies on adequate visualization of their cortical margins to distinguish them from recent fractures of the processes.

Intra-articular synovial folds of thoracolumbar junction zygapophyseal joints

Transverse histological sections from T10-11, T11-12, T12-L1, and L1-2 zygapophyseal joints were examined in 32 post-mortem spines, using light microscopy, to record the presence of intra-articular synovial fold inclusions. In addition, three mid-joint sections from each joint were photographed using 35 mm colour film. From these slides, linear dimensions of the extent of intra-articular synovial fold projection between the zygapophyseal joints were measured using computer-aided planimetry. Small, fibrous folds were commonly found at the joint margins extending from the ligamentum flavum and the fibrous joint capsule. Larger, fibro-adipose synovial folds, projecting between the articular surfaces, were also noted, particularly at T12-L1 and L1-2.

Manual therapy considerations at the thoracolumbar junction: an anatomical and functional perspective

Anatomically, the human thoracolumbar junction demonstrates considerable resistance to rotary motion in an effort to decrease torsional stress through an area of marked functional transition. Despite this, rotational manipulation and mobilization procedures have been advocated in the treatment of painful mechanical disorders originating from the thoracolumbar junction. The rationale behind vigorous manipulative techniques, particularly those incorporating extension, is challenged in light of cadaveric histological studies of this region, as well as both in vivo and experimental biomechanical investigations. Judicious use of traction and mobilization procedures are recommended.

Vertebral body trabecular density at the thoracolumbar junction using quantitative computed tomography. A post-mortem study

Quantitative computed tomography was used to assess vertebral trabecular density in 26 post-mortem spines from individuals aged between 14 and 80 years. All vertebrae from T10 to L1 were scanned transversely near the mid-vertebral level with calculations of trabecular density in HUs averaged and referenced to a mineral equivalent phantom. An age-related decline in trabecular density was recorded (r = 0.55, p less than 0.0001). Density measures from the anterior aspect of the vertebral body were significantly greater than from postero-lateral regions. From T10 to L1, there was a significant decrease in trabecular density, whereas density measures multiplied by vertebral body cross-sectional area were constant. Predictions of vertebral compressive strength using quantitative computed tomography may become more accurate by increasing the sampling area per scan and including vertebral body cross-sectional area as part of the radiologic assessment.

A comparison of radiographic and computer-assisted measurements of thoracic and thoracolumbar sagittal curvature

Sagittal plane curve characteristics of the thoracolumbar spine were evaluated from 286 lateral chest radiographs comparing the Cobb technique with a computer-aided digitizer. Thoracic kyphosis and curve apex were measured from the T3 to T11 segments, and in 120 cases, the level of the thoracolumbar curve inflexion point was determined. An age-related increase in curve magnitude was similar for both measurements, although computer generated kyphosis angles were generally larger. The apex of thoracic kyphosis was consistently located near T7 for males compared with greater variability with age for females. The thoracolumbar inflexion point shifted caudally with increasing years, being most marked for females. The computer method was more reliable, producing a coefficient of variation of 1.4% on repeated measurement. The ability to describe quantitatively the thoracolumbar curve characteristics, calculate angles between selected segments, determine points of inflexion and maximum curvature, indicates that radiographic evaluation of sagittal spinal curvature is improved with the use of computer-aided measurement.

Radiologic study of the influence of zygapophyseal joint orientation on spinal injuries at the thoracolumbar junction

The change from coronal to sagittal plane orientation of the zygapophyseal (facet) joints at the thoracolumbar junction, coupled with differences in lumbar and thoracic spine mobility, may predispose the T10 to L2 segments to injury. To test for an association between the level of injury and variations in orientation of the zygapophyseal joints, CT investigations of 44 spinal injured patients were studied. Of these, 28 sustained burst/compression fractures and 16 demonstrated a rotation injury with disruption to one or both zygapophyseal joints. Injuries were examined to determine whether more congruent "mortice" joints localised the segmental level of trauma. The Chi-square statistic was used: to compare the transitional characteristics of 44 clinical cases with a "normal" patient database (n = 630); to examine differences in transition patterns between the "compression" and "rotation" injury groups; and to compare the incidence of mortice joints between the clinical and normal series. A significant difference between the transition patterns of the clinical and normal series (p less than 0.001) appeared to account for the higher frequency of abrupt transitions in the 44 injury cases. No significant differences distinguished the transition patterns of the two injury groups. A higher incidence of mortice joints was demonstrated in the injury group compared with the normal population (p less than 0.02). These findings suggest that individuals with an abrupt transition have a greater predisposition to injuries at the thoracolumbar junction.

In vivo axial rotation at the thoracolumbar junction: an investigation using low dose CT in healthy male volunteers

Few studies report in vivo data on segmental spinal rotation due to complexities in resolving axial plane motion. Unilateral segmental rotation at the thoracolumbar junction in 18 healthy male volunteers was assessed using a low dose CT protocol. Subjects were positioned in end-range right trunk rotation and, following a digital scanogram, were scanned in the plane of the superior vertebral end-plates of T10-L3. The change in vertebral orientation between mobile segments, assumed to represent 'rotation', was calculated using standardized CT image references and vertebral landmarks. Greatest rotation appeared to occur with coronally oriented joints and the least change between segments where a mortice joint or the thoracolumbar transition was demonstrated. The mean trend was similar for individuals with either an abrupt or gradual change from coronal to sagittal plane orientation of their zygapophysial joints. Although not statistically significant, the gradual pattern demonstrated generally greater rotation at each segmental level compared to those subjects with an abrupt transition pattern. In contrast, routine supine thoracolumbar junction scans of patients showed lesser mean physiological rotation between all segments examined.