Objectives Distal femur fractures can exhibit extensive comminution, and open fractures may result in bone loss. These injuries are under high mechanical demands when stabilized with a lateral locked plate (LLP), and are at risk of non-union or implant failure. This study investigates the optimal LLP screw configuration for distal femur fractures with a large metadiaphyseal gap of 5 cm. Methods A finite element (FE) model, validated against experimentally measured strains and displacement, evaluated pull-out forces and stress concentration on typical implants under clinical conditions corresponding with the 10 % point during the stance phase of the gait cycle. Results Maximum stress was up to 83 % less when the ratio (Cp) between the proximal screw-distribution-length and the distance of the first screw to the fracture was less than 0.2; maximum pull-out force was 99 % less when this ratio was higher than 0.4. Conclusions Screw configuration based on either normal or osteopenic bone quality plays an important role in determining the risk of construct failure for a major (50 mm) distal femoral metadiaphyseal segmental defect. This study provides valuable information when planning definitive fixation for distal femur fractures with extensive comminution or segmental bone defects, to mitigate the risk of implant failure and subsequent nonunion.

(1) Background: Admission to the ICU and intensity of care provided to elderly COVID-19 patients are difficult choices guided by the expected patient-centered benefits. However, the impact of an early discussion of limitation of therapeutic effort (LTE) has been poorly investigated. (2) Methods: We performed a single-center retrospective cohort study including all ≥70-year-old COVID-19 patients admitted to the ICU. Factors associated with early LTE discussion (defined as before or up to 2 days post-ICU admission) and in-hospital mortality were evaluated. (3) Results: Eighty-two patients (59 M/23 F; 78 years (74–82) [median (interquartile range)]; 43/82 with LTE) were included. The in-hospital mortality rate was 55%. Early LTE was decided upon for 22/82 patients (27%), more frequently in older (p < 0.001) and frailer patients (p = 0.004). Using a multivariable logistic regression model including clinical frailty scale grade ≥4, hospital acquisition of COVID-19, ventilation support modality and SOFA score on admission, early LTE was not associated with mortality (adjusted odds ratio = 0.57 (0.15–2.00), p = 0.39). LTE resulted in less frequent invasive mechanical ventilation (23% versus 65%, p = 0.001), renal replacement therapy (5% versus 27%, p = 0.03) and norepinephrine infusion (23% versus 60%, p = 0.005), and shorter ICU stay (6 days (2–12) versus 14 days (7–24), p = 0.001). (4) Conclusions: In this small sample exploratory study, we were unable to demonstrate any increase in in-hospital mortality associated with early LTE discussion in elderly COVID-19 patients while reducing the use of organ support techniques. These findings require confirmation in larger studies.

Context Since recovery or death is generally observed within a few days after intensive care unit (ICU) admission of self-poisoned patients in the developed countries, reasons for the prolonged ICU stay are of interest as they have been poorly investigated. We aimed to identify the characteristics, risk factors, outcome, and predictors of death in self-poisoned patients requiring prolonged ICU management. Methods We conducted an eight-year single-center cohort study including all self-poisoned patients who stayed at least seven days in the ICU. Patients admitted with drug adverse events and chronic overdoses were excluded. Using multivariate analyses, we investigated risk factors for prolonged ICU stay in comparison with a group of similar size of self-poisoned patients with Results Among 2,963 poisoned patients admitted in the ICU during the study period, the number who stayed beyond seven days was small (398/2,963, 13.1%), including 239 self-poisoned patients (125 F/114M; age, 51 years [38-65] (median [25th-75th percentiles]); SAPSII, 56 [43-69]). Involved toxicants included psychotropic drugs (59%), cardiotoxicants (31%), opioids (15%) and street drugs (13%). When compared with patients who stayed <7days in the ICU, acute kidney injury (odds ratio (OR), 3.15; 95% confidence interval (1.36-7.39); p = .008), multiorgan failure (OR, 8.06 (3.43-19.9); p < .001), aspiration pneumonia (OR, 8.48 (4.28-17.3); p < .001), and delayed awakening related to the persistent toxicant effects, hypoxic encephalopathy and/or oversedation (OR, 8.64 (2.58-40.7); p = .002) were independently associated with prolonged ICU stay. In-hospital mortality rate was 9%. Cardiac arrest occurring in the prehospital setting and during the first hours of ICU management (OR, 27.31 (8.99-158.76); p < .001) and delayed awakening (OR, 14.94 (6.27-117.44); p < .001) were independently associated with increased risk of death, whereas exposure to psychotropic drugs (OR, 0.08 (0.02-0.36); p = .002) was independently associated with reduced risk of death. Conclusion Self-poisoned patients with prolonged ICU stay of >= 7days are characterized by concerning high rates of morbidities and poisoning-attributed complications. Acute kidney injury, multiorgan failure, aspiration pneumonia, and delayed awakening are associated with ICU stay prolongation. Cardiac arrest occurrence and delayed awakening are predictive of death. Further studies should focus on the role of early goal-directed therapy and patient-targeted sedation in reducing ICU length of stay among self-poisoned patients.

This study aimed to investigate the use of EOS (bi-planer) imaging and SterEOS reconstruction software to study the efficacy of spinal bracing in adolescent idiopathic scoliosis (AIS).EOS images of scoliosis patients being treated with bracing were obtained both in and out of their brace.These images were processed using SterEOS software to allow 3D representation, which was then compared to traditional coronal 2D parameters.Over a 12-month period 29 patients were recruited for participation.Of these participants, 25 had a single episode of EOS imaging out of and in their brace.Additionally, 19 of the 25 participants had further episodes of EOS imaging within the study period, separated by mean 144+/-44 days.This allowed a total of 44 EOS single scan episodes for parameter analysis out of, and in the brace.Longitudinal analysis was also performed on the 19 patients who had sequential scans.Participants were mean 13.8 ± 1.1 years old at the first scan.Coronal 2D parameters, specifically Cobb Angle measurement, were accurately reproducible with SterEOS 3D measurements.Across all EOS scans (n = 44) the mean major coronal curve measurement was 42.3 ± 13.3° out of brace and 37.2 ± 13.8° in the brace.This produced a mean correction of 4.6 ± 4.4° (p < 0.05).The correction achieved in this cohort with bracing appeared more modest than those reported in previous studies using traditional 2D coronal curve measurements [1-3].The mean axial vertebral rotation (AVR) was 10.6 ± 7.1° out of the brace and 9.6 ± 6.8° in the brace, with a mean correction of 1.4 ± 5.3°(p = 0.14).The current study results suggested no significant change in axial vertebral rotation with brace treatment.Notably, in 17 of the 44 AVR measured, the differences were negative.That is, the AVR worsened in the brace.There was a significant moderate correlation between 3D coronal Cobb angle measured and AVR measured out of the brace for all curves.However, the change in Cobb and change in AVR with bracing did not correlate.Over sequential EOS episodes (n = 19), there appeared no significant progression of 3D parameters.There appeared to be a consistent reduction in the scoliosis Cobb angle of the major curve with brace treatment.AVR demonstrated no significant change with bracing, with instances of worsening of AVR in the brace, which was not reflected by Cobb angle measurement.Despite this, bracing appears to have limited curve progression in sequential scans, though not in the anticipated manner of immediate in-brace curve correction.

Purpose. This study aimed to investigate the efficacy of spinal bracing in treating progressive scoliosis deformity utilizing EOS (bi-planer) imaging and SterEOS reconstruction software. Methods. EOS images of scoliosis patients being treated with bracing were obtained both in and out of their brace. These images were processed using SterEOS software to allow 3D representation, which was then compared to traditional coronal 2D parameters. Between January 2019 and January 2020, 29 patients were recruited for participation. Of these participants, 25 had a single episode of EOS imaging out of and in their brace. Additionally, 19 of the 25 participants had further episodes of EOS imaging within the study period, separated by mean 144+/-44 days. This allowed a total of 44 EOS single scan episodes for parameter analysis out of, and in the brace. Longitudinal analysis was also performed on the 19 patients who had sequential scans. Results. Participants were mean 13.8±1.1 years old at the first scan. Coronal 2D parameters, specifically Cobb Angle measurement, were accurately reproducible with SterEOS 3D measurements. Across all EOS scans (n=44) the mean major coronal curve measurement was 42.3±13.3° out of brace and 37.2±13.8° in the brace. This produced a mean correction of 4.6±4.4° (p<0.05). The correction achieved in this cohort with bracing appeared more modest than those reported in previous studies using traditional 2D coronal curve measurements 1–3 . The mean axial vertebral rotation (AVR) was 10.6±7.1° out of the brace and 9.6±6.8° in the brace, with a mean correction of 1.4±5.3°(p=0.14). The current study results suggested no significant change in axial vertebral rotation with brace treatment. Notably, in 17 of the 44 AVR measured, the differences were negative. That is, the AVR worsened in the brace. There was a significant moderate correlation between 3D coronal Cobb angle measured and AVR measured out of the brace for all curves. However, the change in Cobb and change in AVR with bracing did not correlate.Over sequential EOS episodes (n=19), there appeared no significant progression of 3D parameters, interpreted as the brace preventing curve progression. Conclusions. There appeared to be a consistent reduction in the scoliosis Cobb angle of the major curve with brace treatment. AVR demonstrated no significant change with bracing, with instances of worsening of AVR in the brace, which was not reflected by Cobb angle measurement. Despite this, bracing appears to have been effective with limited curve progression in sequential scans, though not in the anticipated manner of immediate in-brace curve correction.

(1) Background: Corticosteroids lower 28-day all-cause mortality in critically ill COVID-19 patients. However, the outcome of COVID-19 patients referred to the intensive care unit (ICU) for respiratory deterioration despite corticosteroids initiated during hospitalization before ICU admission has been poorly investigated. Our objective was to determine survival according to corticosteroid initiation setting. (2) Methods: We conducted a cohort study including all successive critically ill COVID-19 patients treated with corticosteroids and managed in our ICU. We compared survival, whether corticosteroids were initiated before (Cb-group) or after ICU admission (Ca-group), using a propensity score matching. (3) Results: Overall, 228 patients (67 years (56–74); 168M/60F; invasive mechanical ventilation on admission, 17%) were included with 63 patients in the Cb-group and 165 patients in the Ca-group. Survival to hospital discharge was 43% versus 69%, respectively (p = 0.001). In a multivariable analysis, factors associated with death were age (odds ratio, 1.07; 95%-confidence interval, (1.04–1.11); p < 0.0001), the sequential organ failure assessment (SOFA) score on ICU admission (1.30 (1.14–1.50); p = 0.0001) and corticosteroid initiation before ICU admission (2.64 (1.30–5.43); p = 0.007). No significant differences in outcome related to corticosteroid regimen were found. (4) Conclusions: Critically ill COVID-19 patients transferred to the ICU with deterioration despite corticosteroids initiated before admission have a less favorable outcome than patients receiving corticosteroids initiated after ICU admission.

Cross-sectional study. To provide a comprehensive, multi-stage investigation of vertebral body (VB) and intervertebral disc (IVD) coronal plane deformities for adolescent idiopathic scoliosis (AIS) patients with a main thoracic curve type, using a series of sequential magnetic resonance images (MRIs). Despite numerous investigations of AIS deformity at the spinal segmental level, there is little consensus as to the major contributor to the lateral curvature of a scoliotic spine. Moreover, scoliotic deformity is often described along a continuum of progression, with few studies having characterised the change in segmental deformity for AIS patients whose deformity progresses clinically over time. 30 female AIS patients with primary thoracic curves were included between 2012 and 2016. Three sequential MRIs were captured for each patient. Datasets were reformatted to produce true coronal plane images of the thoracic spine (T4–L1). Overall curve morphology, coronal plane IVD and VB segmental deformity and rates of growth were analysed. Right-side asymmetry was greater in IVDs (18.5 ± 23.9%) when compared to VBs (8.3 ± 9.2%) (P < 0.05) by third scans. Despite this, 77% of patients demonstrated the majority (> 50%) of their coronal curvature was attributed to VB wedging when measured across all three scans. Regardless of progression status, scan number, or region, the sum of the VB wedging angle was greater than the sum of the IVD wedging angle (all P ≤ 0.05). There was no correlation between the rates of major curve angle progression and standing height increase, VB height growth, or IVD height growth (P > 0.05). VB wedging contributed more to the lateral deformity observed in primary thoracic subtypes of AIS patients than IVD wedging. While IVDs demonstrated the greatest asymmetric deformity, their relatively smaller height resulted in a smaller proportional change in lateral curve angle compared to the VBs. IV.

Study design Prospective cohort study. Objectives Investigate the progressive changes in pedicle morphometry and the spatial relationship between the pedicles and neurovascular structures in patients with AIS during growth. Summary of background data Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional spine deformity. AIS pedicles are known to be asymmetrical when compared to adolescents without scoliosis. Defining the anatomical changes occurring progressively in scoliosis as it increases with time and growth is essential for understanding the pathophysiology of scoliosis and for treatment planning. MRI is the ideal method to study the growing spine without ionising radiation. Methods 24 females with AIS (mean 12.6 years, right sided main thoracic curves) and 20 non-scoliotic females (mean 11.5 years) were selected from an ongoing database. Participants underwent two 3D MRI scans (3 T scanner, T1, 0.5 mm isotropic voxels) approximately 1 year apart (AIS: mean 1.3 ± 0.05 years, control: mean 1.0 ± 0.1 years). The pedicle width, chord length, pedicle height, transverse pedicle angle, sagittal pedicle angle, distance from vertebrae to aorta and distance from pedicle to dural sac were measured from T5 to T12. Inter- and intra-observer variability was assessed. Results From scans 1–2 in the AIS group, the dural sac became closer to the left pedicle ( p < 0.05, T6, T8–T10 and T12) while the distance from the vertebrae to the aorta increased ( p < 0.05, T6–T10). No significant changes in these measurements were observed in the non-scoliotic group. Between scans, the AIS chord length and transverse pedicle angle increased on the left side around the apex ( p < 0.05) creating asymmetries not seen in the non-scoliotic cohort. The mean pedicle height increased symmetrically in the non-scoliosis cohort ( p < 0.05) and asymmetrically in the AIS group with the right side growing faster than the left at T6–T7 ( p < 0.05). Conclusion Asymmetrical growth patterns occur in the vertebral posterior elements of AIS patients compared to the symmetrical growth patterns found in the non-scoliotic participants. Level of evidence Level II prospective comparative study.

A fiducial marker displays on an image as a distinct high intensity region to pinpoint specific landmarks and pathologies as well as allowing images from different sources to be registered against each other. While commercial markers are clearly visualised in magnetic resonance images (MRI), they are expensive and typically single use, making the cost of research requiring multiple markers prohibitive. We assessed various ‘everyday’ items, to find a reliable alternative to commercial surface fiducial markers. Depending on the MRI sequence required, four alternative cheap and easily sourced markers were determined. The fish oil capsule is already commonly used in clinical MRI departments but the capsule is too large for some applications and is a rupture risk under body weight. Ultimately, the Vitamin D capsule provided an excellent balance between availability, size, cost, usability and quality of visualisation for all the common MRI sequences analysed.

INTRODUCTION A plethora of measurements are available to characterise scoliosis, but a mismatch remains between cosmesis, radiological parameters and patient functional outcomes. Better assessment of cosmesis, through quantitative techniques, may help address this mismatch. We propose a new method of quantifying external scoliotic deformity, by assessing rotation and symmetry in transverse slices across the length of the torso, using 3D photography. METHODS 3D surface scanning is conducted routinely at the Queensland Children’s Hospital spine deformity clinic, for patients with a diagnosis of Adolescent Idiopathic Scoliosis (AIS). From an ongoing database of pre- and post-operative scans a series of 6 patients with similar curve type (Lenke Type 1) were selected for analysis. Lenke Type 1 is defined as major thoracic structural curves, with any adjacent curves present being deemed compensatory. The mean age pre-operatively was 15.4 ± 1.6 years, and the mean major curve Cobb angle was 65.7 ± 13.3deg. 3D scans were captured (Artec Eva, Artec Group Inc., Luxembourg) at the preoperative surgical planning appointment, and again at either their immediate postoperative (6-8 weeks), or subsequent follow up appointments (6-12 months). Using the surface scan data, 3D virtual representations of the patient’s standing body shape were created (Figure 1). From these reconstructions, transverse cross-sectional profiles for the outer torso skin surface were created at 10% intervals between their pelvis and C7 prominence. A line of maximum symmetry was determined, that defined the angle of rotation of each profile (positive: right) relative to the sagittal plane. The range of profile rotations along the length of each individual patient’s spine (minimum to maximum) was compared pre- to post-operatively. Additionally the ratio of corresponding pixels about the line of maximum symmetry of each profile was assessed along the length of the spine, pre- and post-operatively. A healthy adult female with no spinal deformity, who underwent a 3D scan for the purposes of another research project was included as a reference. RESULTS AND DISCUSSION The selected patients saw a dramatic improvement in their major curve angle – the traditional common measure of surgical correction. The mean decrease was 42.2 ± 10.3 deg. A concurrent increase in standing height was also seen of between 0.2 – 5.6cm (mean 3.0cm). Torso profile rotations varied in magnitude between participants but the pattern was consistent and matched the curve type. Maximum rotation was seen at levels 4 and 5, approximately the T9-T11 rib region, corresponding with major curve apexes at T8-9 to T10-11. Decreases in the maximum rotation and the total range of rotations were seen post-operatively, particularly around the peak areas of profiles 4-6. In comparison, the healthy participant had a very consistent rotation of 3.4±0.5deg. All profiles included in the analysis had symmetry values between 90% and 100% (52 out of 53 were greater than 94%). Some proximal torso profiles that included the shoulders and neck were excluded because of clothing or postural issues. The healthy participant showed a mean symmetry value of 98.8% ± 0.60%. Increases in symmetry were seen in the study subjects after surgery. Profile 4 in particular showed the largest increase in symmetry (range 3.0% – 6.8%), with smaller changes found in the upper thoracic regions. CONCLUSIONS Torso segmental rotations and symmetry provide a metric to describe the externally visible trunk deformity associated with AIS. Main thoracic structural curves often involve a large degree of both anterior and posterior rib cage deformity that is not well characterised clinically. 3D photography has the potential to provide such a metric.

Objectives Single-use commercial surface fiducial markers are used in clinical imaging for a variety of applications. The current study sought to find a new, reliably visible, easily sourced and inexpensive fiducial marker alternative for use with MRI. Design Five commonly requested MRI sequences were determined (three-dimensional (3D) T1-weighted, T1 coronal, 3D T2-weighted, T2 fat suppressed, proton density), to examine the visibility of 18 items (including a commercial fiducial marker). Setting Clinical 3T MRI scanner in an Australian Tertiary Hospital and an Australian University Biomedical Engineering research group. Interventions 18 marker alternatives were scanned using five common MRI sequences. Images were reformatted to obtain both an image through the mid-height of each marker and a maximum intensity z-projection image over the volume of the marker. Variations in marker intensity were profiled across each visible marker and a visibility rating defined. Main outcome measures Outcome measures were based on quantitative assessment of a clear intensity contrast ratio between the marker and the adjacent tissue and a qualitative assessment of visibility via a 3-point scale. Results The fish oil capsule, vitamin D capsule, paint ball pellet, soy sauce sushi tube and commercial markers were typically visible to a high quality on all the imaging sequences and demonstrated a clear differential in intensity contrast against the adjacent tissue. Other common items, such as plasticine 'play doh' and a soft 'Jelly baby' sweet, were surprise candidates, demonstrating high-quality visibility and intensity contrast for the 3D T1-weighted sequence. Conclusions Depending on the basis for referral and MRI sequence chosen, four alternative fiducial markers were determined to be inexpensive, easily sourced and consistently visible. Of these, the vitamin D capsule provided an excellent balance between availability, size, cost, usability and quality of the visualised marker for all the commonly used MRI sequences analysed.

Externally visible deformity (rib hump or ribcage asymmetries) is a cosmetic feature of great concern for Adolescent Idiopathic Scoliosis (AIS) patients. Current assessment techniques for AIS do not fully encompass the external deformity. A non-invasive method capable of capturing superficial anatomy would enable better qualitative and quantitative evaluation of cosmesis. Handheld 3D scanners rapidly capture high resolution 3D scans of surface features. This study aimed to quantify the accuracy of three commonly available scanners, in assessing posterior asymmetry in AIS.

A complex relationship between deformity progression and level-wise deformity (vertebral, VB, and intervertebral disc, IVD) exists for adolescent idiopathic scoliosis (AIS) patients. The current study developed upon prior work, to compare the progressive changes in VB and IVD height for a larger cohort of both AIS patients and non-scoliotic controls, using sequential MRI scans. These findings have relevance in establishing standardised growth patterns for AIS patients.

A fiducial marker is an object placed in the field of view of an image to provide as a point of reference. For example, a ruler placed next to an object in a photograph to demonstrate the size of the object is a commonly seen fiducial. Fiducial markers used in the context of medicine may be implanted within the body part of interest or placed externally on the surface. Non-implantable fiducial markers are used in clinical imaging for a variety of applications. They are placed in the field of view of the scanner or attached externally to the anatomy, and they display as distinct regions of high intensity. As such, they assist in pinpointing specific anatomical landmarks or pathologies on the acquired clinical images as well as allowing images of the same subject produced with different imaging systems to be correlated or registered against each other. While commercially available fiducial markers are easily identifiable and clearly visualised in magnetic resonance images (MRI), they are expensive and typically single use, making the cost of research studies where multiple markers are required for numerous subjects prohibitive. For this reason, the current study sought to assess the validity of various ‘everyday’ items, which could be easily and economically sourced, to provide a reliable alternative to the comparatively expensive commercial fiducial markers.

The sternum and ribs play a significant role in providing stiffness to the thoracolumbar spine, however, the relative mechanical contribution of the ribs and intercostal soft tissue connections is less clear. In a prior biomechanical study from our group, the contribution of the sternum, ribs and intercostal soft tissues in influencing spinal stiffness was measured. Using these biomechanical data, the current computational study sought to develop a validated representation of ribcage mechanics, using an established workflow for creating subject specific finite element (FE) models of the thoracolumbar spine with ribcage. This study has highlighted the importance of accurately replicating both the anatomy and mechanical nature of osseous and soft tissue structures in the ribcage, particularly if models are to provide useful insight into spinal pathologies, injuries or surgery which involve disruption to the intercostal soft tissues.

Quantifying varying pedicle growth and relationships to neurovascular structures in healthy adolescents compared to Adolescent Idiopathic Scoliosis (AIS) patients is critical for understanding the pathology of AIS and for implementing treatment options. This study used sequential MRI scans of AIS patients and non-scoliotic control subjects to quantitatively document these anatomical changes with time. This knowledge will enhance our understanding of the pathological development of AIS and may aid in both non-surgical and surgical treatment options.

Three dimensional (3D) reconstructions of the spinal vertebrae have been utilised to create computational models for assessing spinal biomechanics. Direct segmentation of bony anatomy from magnetic resonance imaging (MRI) is not straightforward. In light of the non-irradiating advantages offered by this imaging modality for routine scanning of patients, the current project sought to develop an efficient, accurate and semi-automatic method for reconstructing spinal vertebra anatomy from clinical MRI. An accurate, semi-automated technique was developed to segment and reconstruct lumbar vertebral anatomy using MRI data. This technique resulted in reconstructed vertebral anatomy with clearly defined vertebral bodies as well as posterior elements, something hereto not achieved in prior studies. The technique is sensitive to the quality of bone imaged and geometric accuracy may be reduced for aged bone.

Relative overgrowth of the anterior spinal column has been postulated as a key driver of spinal deformity in scoliosis, with recent work suggesting most of the excessive growth occurs in the intervertebral discs (IVD). The aim of this study was to compare disc growth between scoliosis patients and healthy controls. The study cohort comprised 36 healthy female adolescents and 28 Adolescent Idiopathic Scoliosis (AIS) patients. IVD mean heights from T4-L1 were measured in the coronal plane from endplate to endplate and compared to vertebral body (VB) heights and standing height on the day of the scan for two separate scans for each participant. This study showed that IVD height growth in the adolescent thoracic spine is negligible over intervals of approximately one year for both AIS patients and healthy participants. Measurable increases in vertebral body height do occur however, and it is these that most likely drive any increases in overall spinal length.

In Adolescent Idiopathic Scoliosis (AIS) the cross-sectional area of the spinal cord and spinal canal is of clinical importance when inserting pedicle screws. Few studies have measured the size of the canal and cord in adolescents, or how they change over time. This study quantified the axial cross-sectional area of both the spinal cord and spinal canal in healthy adolescents and those with AIS over time.

Previous studies examining the kinematics of the thoracolumbar spine and rib cage have been limited by the number of motion segments for which motion was tracked. Additionally, the biomechanical effect of the soft and osseous tissue structures of the rib cage on the segmental motion of the spine has not been fully quantified. While previous investigations have examined changes in spinal segmental rotation in the plane of primary motion, little has been done to examine the out of plane motion or how these tissue structures affect the magnitude and directions of spinal movement. This study therefore aimed to determine the three-dimensional movement of all motion segments in the thoracolumbar spine, with the spine in an intact state and following progressive dissection of the ribcage, including resection of the intercostal muscles, cutting of the sternum, and removal of the ribs. The soft and osseous tissues of the rib cage play an important part in the movement of the whole spine, both in the primary direction of rotation and in coupled out of plane rotations. In lateral bending, the intact spine showed the largest flexion/extension movements. In direct contrast, removing either soft or osseous rib cage tissues increased the lateral rotations occurring during flexion. The observed coupled rotations and their changes with dissection are important considerations for computational modelling of the biomechanical behaviour of the spine and have clinical relevance in studying biomechanical aspects of pathologies such as scoliosis, which involve atypical rotation of the spinal vertebral bodies.