Biomechanics of Human Thoracic Ribs

Considerable advances have been made to determine the failure biomechanical properties of the human thoracic spinal column and its components. Except for a few fundamental studies, there is a paucity of such data for the costovertebral elements. The present study was designed to determine the biomechanics of the human thoracic spine ribs from a large population. Seventh and eighth ribs bilaterally were tested from 30 human cadavers using the principles of three-point bending techniques to failure. Biomechanical test parameters included the cross-sectional area (core, marrow, and total), moment of inertia, failure load, deflection, and the Young’s elastic modulus. The strength-related results indicated no specific bias with respect to anatomical level and hemisphere (right or left), although the geometry-related variables demonstrated statistically significant differences (p < 0.05) between the seventh and the eighth ribs. This study offers basic biomechanical information on the ultimate failure and geometric characteristics of the human thoracic spine ribs.

Download Full-text

The effects of ovariectomy on bone mineral density, geometrical, and biomechanical characteristics in the rabbit femur

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.3415/vcot-08-09-0085 ◽

2010 ◽

Vol 23 (01) ◽

pp. 31-36 ◽

Cited By ~ 7

Author(s):

M. E. Kara ◽

F. Sevil

Keyword(s):

Bone Mineral Density ◽

Bone Mineral ◽

Animal Studies ◽

Biomechanical Properties ◽

Mineral Density ◽

Cross Sectional ◽

Tomographic Images ◽

Three Point Bending ◽

Rabbit Femur

SummaryThe aim of the study was to evaluate the bone mineral density, as well as the biomechanic and morphometric changes in the femur of ovariectomised rabbits.Twenty-four six-month-old New Zealand rabbits were randomly divided into an ovariectomy (n = 12) and a sham (n = 12) group. Six rabbits in each group were euthanatized at eight and 16 weeks after surgery, and the femora were resected. The morphometric data were obtained from tomographic images. Periosteal and endosteal diameters and cortical thickness were measured. Total cross-sectional, cortical and medullary areas were also measured. The bone mineral content, the bone area and the bone mineral density were measured from the proximal, distal and mid-shaft of the femur as well as the total femur by dual energy X-ray absorptiometry. Employing the three-point bending method, the ultimate force, stiffness and work-to-failure were measured. The mechanical data were normalised to obtain intrinsic biomechanical properties such as ultimate stress, elastic modulus, and toughness, all of which are independent of size and shape.The results indicated that the femur was both larger and weaker 16 weeks after surgery in the ovariectomised group. Results also suggest that the rabbit might be a useful animal model for investigation of diseases related to oestrogen loss such as human postmenopausal osteoporosis. However, additional studies with advanced techniques at several time points via in vivo animal studies, and precision and predictability analyses should be designed to standardise the rabbit as a model for osteoporosis.

Download Full-text

Thoracic spinal disease

Oxford Textbook of Neurological Surgery ◽

10.1093/med/9780198746706.003.0061 ◽

2019 ◽

pp. 711-718

Author(s):

Kieron Sweeney ◽

Catherine Moran ◽

Ciaran Bolger

Keyword(s):

Cervical Spine ◽

Thoracic Spine ◽

Osteoporotic Fractures ◽

Biomechanical Properties ◽

Minimally Invasive Techniques ◽

Disc Prolapse ◽

Disc Disease ◽

Thoracic Spinal ◽

Thoracic Disc ◽

Invasive Techniques

The thoracic spine occupies a unique position with respect to anatomical, biomechanical, pathological, and surgical considerations. The kyphosis of the thoracic spine is offset by the lordosis in the mobile cervical spine and the principal load bearing lumbar spine maintaining a sagittal balanced posture. Due to the biomechanical properties of the thoracic spine, the incidence of thoracic disc prolapse is low. However, the anatomical features of the thoracic spine make appropriate surgical planning imperative. This chapter will cover the management and operative approaches to thoracic disc disease, including open and minimally invasive techniques. Operative approaches can be broadly divided into two groups, anterior and posterior-lateral. Each approach is discussed with respect to technique, anatomy, closure, and common complications. It will also discuss pathogenesis, diagnosis, and management of osteoporotic fractures.

Download Full-text

Biomechanical properties and thermal characteristics of frozen versus thawed whole bone

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/0954411920929455 ◽

2020 ◽

Vol 234 (8) ◽

pp. 874-883

Author(s):

Ignace J Brazda ◽

Jacob Reeves ◽

G Daniel G Langohr ◽

Meghan C Crookshank ◽

Emil H Schemitsch ◽

...

Keyword(s):

Steady State ◽

Thermal Characteristics ◽

Ambient Air ◽

Biomechanical Properties ◽

Mechanical Tests ◽

Mineral Density ◽

Cross Sectional ◽

Three Point Bending ◽

Transverse Cracking ◽

Steady State Temperature

Biomechanics research often requires cadaveric whole bones to be stored in a freezer and then thawed prior to use; however, the literature shows a variety of practices for thawing. Consequently, this is the first study to report the mechanical properties of fully frozen versus fully thawed whole bone as ‘proof of principle’. Two groups of 10 porcine ribs each were statistically equivalent at baseline in length, cross-sectional area, and bone mineral density. The two groups were stored in a freezer for at least 24 h, thawed in air at 23 °C for 4 h while temperature readings were taken to establish the time needed for thawing, and once again returned to the freezer for at least 24 h. Mechanical tests to failure using three-point bending were then done on the ‘frozen’ group immediately after removal from the freezer and the ‘thawed’ group when steady-state ambient air temperature was reached. Temperature readings over the entire thawing period were described by the line-of-best-fit formula T = (28.34t − 6.69)/(t + 0.38), where T = temperature in degree Celsius and t = time in hours, such that frozen specimens at t = 0 h had a temperature of −17 °C and thawed specimens at t = 1.75 h reached a steady-state temperature of 20 °C–23 °C. Mechanical tests showed that frozen versus thawed specimens had an average of 32% higher stiffness k, 34% higher ultimate force Fu, 28% lower ultimate displacement δu, 40% lower ultimate work Wu, 43% higher elastic modulus E, 37% higher ultimate normal stress σu, and 33% higher ultimate shear stress τu. Whole ribs failed at midspan primarily by transverse cracking (16 of 20 cases), oblique cracking (three of 20 cases), or surface denting (one of 20 cases), each having unique shapes for force versus displacement graphs differentiated mainly by ultimate force location.

Download Full-text

Biomechanical Evaluation of the MACSTL Internal Fixator for Thoracic Spinal Stabilisation

Acta Veterinaria Brno ◽

10.2754/avb200877010097 ◽

2008 ◽

Vol 77 (1) ◽

pp. 97-102 ◽

Cited By ~ 3

Author(s):

R. Veselý ◽

Z. Florián ◽

P. Wendsche ◽

J. Tošovský

Keyword(s):

Thoracic Spine ◽

Spinal Column ◽

Spinal Fractures ◽

Internal Fixator ◽

Additional Advantage ◽

System A ◽

Thoracic Spinal ◽

Mechanical Study ◽

Surgical Tactics ◽

The Stability

Unstable fractures of the thoracic spine in humans represent a serious social and economic issue. They may lead to persistent consequences and chronic disease. The anatomical and biomechanical characteristics of the thoracic spine are different from all the other spinal parts due to its higher mobility. The vertebrae of the chest area are less mobile, conferring a higher degree of rigidity to the spine. To destabilize this relatively rigid system, a considerable force is necessary. The treatment of unstable spinal fractures is solely surgical. The decompression of the spinal canal with reposition and stabilisation of the fracture is indicated urgently. This intervention is performed mostly from the posterior approach in the first phase. However, the anterior spinal column is the structure responsible for the stability of the spine. Therefore, the recent advances in spine surgery focus on this area of expertise. For this reason, we carried out a bio-mechanical study aimed at assessing the effectiveness of two surgical tactics used. The study consisted of comparative experiments performed by computer-aided device on segments of pig cadavers (n = 5). The experiment involved a comparison of segments of the thoracic spine under the following conditions: an anatomically intact segment, a spine segment with an artificially created anterior instability, and a segment with an applied internal fixator. The experiment compared the mechanical characteristics of these segments. The experiment has demonstrated that after application of the internal fixator used for stabilisation of the injured anterior spinal column at defined pre-loading of 200 N, the stability of damaged spinal segment in torsion increased twofold. It was also verified that sufficient stability can be ensured using the Modular Anterior Construct System (MACSTL) implant for ventral stabilisation of thoracic spine unstable injuries. Endoscopic application of this implant represents an additional advantage of this surgical procedure.

Download Full-text

Three-point bending test parameters for dental materials evaluation

Dental Materials ◽

10.1016/j.dental.2012.07.012 ◽

2012 ◽

Vol 28 ◽

pp. e2-e3

Author(s):

B.C.F. Barreto ◽

L.H.A. Raposo ◽

S.J.B. Sousa ◽

A.G. Pereira ◽

A. Versluis ◽

...

Keyword(s):

Dental Materials ◽

Bending Test ◽

Three Point Bending ◽

Test Parameters

Download Full-text

Monostotic fibrous dysplasia of the thoracic spine: clinopathological description and follow up

Journal of Neurosurgery Spine ◽

10.3171/spi.2004.100.4.0378 ◽

2004 ◽

Vol 100 (4) ◽

pp. 378-381 ◽

Cited By ~ 3

Author(s):

Mehmet Arazi ◽

Onder Guney ◽

Mustafa Ozdemir ◽

Omer Uluoglu ◽

Nuket Uzum

Keyword(s):

Fibrous Dysplasia ◽

Thoracic Spine ◽

Histopathological Examination ◽

En Bloc Resection ◽

Spinal Tumors ◽

En Bloc ◽

Content Type ◽

Thoracic Spinal ◽

Fine Print

✓ The authors report the case of a 53-year-old woman with monostotic fibrous dysplasia of the thoracic spine. The patient presented with a 1-month history of pain in the thoracic spinal region. En bloc resection of the lesion was successfully performed via a transthoracic approach, and a histopathological examination confirmed the diagnosis of fibrous dysplasia. At 24-month follow-up examination, pain and vertebral instability were absent. The findings in this case illustrate that, although very rare, monostotic fibrous dysplasia of the thoracic spine should be considered in the differential diagnosis of spinal tumors. Although a consensus for management of this disease has not been achieved, the authors recommend radical removal of all involved bone as well as internal fixation or bone graft—assisted fusion to achieve long-term stabilization.

Download Full-text

Socio-Economic Status and Prevalence of Self-Reported Osteoporosis in Tehran: Results from a Large Population-Based Cross-Sectional Study (Urban HEART-2)

Journal of Urban Health ◽

10.1007/s11524-018-0246-6 ◽

2018 ◽

Vol 95 (5) ◽

pp. 682-690 ◽

Cited By ~ 2

Author(s):

M. Asadi-Lari ◽

Y. Salimi ◽

M. R. Vaez-Mahdavi ◽

S. Faghihzadeh ◽

A. A. Haeri Mehrizi ◽

...

Keyword(s):

Economic Status ◽

Large Population ◽

Population Based ◽

Cross Sectional Study ◽

Sectional Study ◽

Cross Sectional ◽

Socio Economic Status

Download Full-text

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.675 ◽

2010 ◽

Vol 638-642 ◽

pp. 675-680 ◽

Cited By ~ 6

Author(s):

Martina Thomann ◽

Nina von der Höh ◽

Dirk Bormann ◽

Dina Rittershaus ◽

C. Krause ◽

...

Keyword(s):

Mechanical Properties ◽

Cross Sections ◽

Degradation Process ◽

Cross Sectional Area ◽

Bending Test ◽

Sectional Area ◽

Cross Sectional ◽

Initial Strength ◽

Three Point Bending ◽

The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

Download Full-text

Incidence and Risk Factors for Symptomatic Spinal Epidural Hematoma Following Posterior Thoracic Spinal Surgery in a Single Institute

Global Spine Journal ◽

10.1177/2192568220979141 ◽

2020 ◽

pp. 219256822097914

Author(s):

Longjie Wang ◽

Hui Wang ◽

Zhuoran Sun ◽

Zhongqiang Chen ◽

Chuiguo Sun ◽

...

Keyword(s):

Risk Factors ◽

Cerebrospinal Fluid ◽

Spinal Surgery ◽

Cerebrospinal Fluid Leakage ◽

Sectional Area ◽

Kyphosis Angle ◽

Cross Sectional ◽

Thoracic Spinal ◽

Local Kyphosis ◽

Spinal Epidural

Study Design: Case-control study. Objectives: To investigate the incidence of symptomatic spinal epidural hematoma (SSEH) and recognize its risk factors in a cohort of patients undergoing posterior thoracic surgery in isolation. Methods: From January 2010 to December 2019, patients who developed SSEH after posterior thoracic surgery and underwent hematoma evacuation were enrolled. For each SSEH patient, 2 or 3 controls who did not develop SSEH and underwent the same procedures with similar complexity at the same section of the thoracic spine in the same period were collected. The preoperative and intraoperative factors, blood pressure-related factors and radiographic parameters were collected to identify possible risk factors by comparing between the 2 groups. Results: A total of 24 of 1612 patients (1.49%) were identified as having SSEH after thoracic spinal surgery. Compared to the control group (53 patients), SSEH patients had significant differences in the APTT (p = 0.028), INR (p = 0.009), ratio of previous spinal surgery (p = 0.012), ratio of cerebrospinal fluid leakage (p = 0.004), thoracic kyphosis (p<0.05), local kyphosis angle (p<0.05), epidural fat ratio at T7 (p = 0.003), occupying ratio of the cross-sectional area (p<0.05) and spinal epidural venous plexus grade (p<0.05). Multiple logistic regression analysis revealed 3 risk factors for SSEH: cerebrospinal fluid leakage, the local kyphosis angle (>8.77°) and the occupying ratio of the cross-sectional area (>49.58%). Conclusions: The incidence of SSEH was 1.49% in posterior thoracic spinal surgeries. Large local kyphosis angle (>8.77°), high occupying ratio of cross-sectional area (>49.58%) and cerebrospinal fluid leakage were identified as risk factors for SSEH.

Download Full-text