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European Spine Journal : Official... Sep 2023To test whether multiple-level unilateral thoracic spinal nerves (TSN) resection can induce the initial thoracic cage deformity to cause early onset thoracic scoliosis...
PURPOSE
To test whether multiple-level unilateral thoracic spinal nerves (TSN) resection can induce the initial thoracic cage deformity to cause early onset thoracic scoliosis in an immature porcine model; and 2) to create an early onset thoracic scoliosis in a large animal model that can be used to evaluate growth-friendly surgical techniques and instruments in growing spine researches.
METHODS
Seventeen one-month-old pigs were assigned to 3 groups. In group 1 (n = 6), right TSN were resected from T7 to T14 with the contralateral (left) paraspinal muscle exposing and stripping. In group 2 (n = 5), the animals were treated in the same way except the contralateral (left) side was intact. In group 3 (n = 6), bilateral TSN were resected from T7 to T14. All animals were followed up for 17-weeks. Radiographs were measured and analyzed the correlation between the Cobb angle and thoracic cage deformity. A histological examination of the intercostal muscle (ICM) was performed.
RESULTS
In the groups 1 and 2, an average 62 ± 12° and 42 ± 15° right thoracic scoliosis with apical hypokyphosis of a mean - 5.2 ± 16° and - 1.8 ± 9° were created, respectively, during 17-weeks follow up. All curves were located at the operated levels with the convexity toward the TSN resection side. Statistical analysis demonstrated that the thoracic deformities were strongly correlated with the Cobb angle. In group 3, no scoliosis was created in any animal, but an average thoracic lordosis of - 32.3 ± 20.3° was seen. The histological examination showed the ICM denervation on the TSN resection side.
CONCLUSION
Unilateral TSN resection induced the initial thoracic deformity toward the TSN resection side resulting in thoracic hypokyphotic scoliosis in an immature pig model. This early onset thoracic scoliosis model could be used to evaluate the growth-friendly surgical techniques and instruments in future growing spine researches.
Topics: Animals; Swine; Thoracic Vertebrae; Disease Models, Animal; Scoliosis; Radiography; Spinal Nerves
PubMed: 37330938
DOI: 10.1007/s00586-023-07804-3 -
Anatomical Record (Hoboken, N.J. : 2007) Aug 2009Spontaneous vertebral fractures are a common occurrence in modern humans, yet these fractures are not documented in other hominoids. Differences in vertebral bone... (Comparative Study)
Comparative Study
Spontaneous vertebral fractures are a common occurrence in modern humans, yet these fractures are not documented in other hominoids. Differences in vertebral bone strength between humans and apes associated with trabecular bone microarchitecture may contribute to differences in fracture incidence. We used microcomputed tomography to examine trabecular bone microarchitecture in the T8 vertebra of extant young adult hominoids. Scaled volumes of interest from the anterior vertebral body were analyzed at a resolution of 46 microm, and bone volume fraction, trabecular thickness, trabecular number, trabecular separation, structure model index, and degree of anisotropy were compared among species. As body mass increased, so did trabecular thickness, but bone volume fraction, structure model index, and degree of anisotropy were independent of body mass. Bone volume fraction was not significantly different between the species. Degree of anisotropy was not significantly different among the species, suggesting similarity of loading patterns in the T8 vertebra due to similar anatomical and postural relationships within each species' spine. Degree of anisotropy was negatively correlated with bone volume fraction (r(2) = 0.85, P < 0.05) in humans, whereas the apes demonstrated no such relationship. This suggested that less dense human trabecular bone was more preferentially aligned to habitual loading. Furthermore, we theorize that trabeculae in ape thoracic vertebrae would not be expected to become preferentially aligned if bone volume fraction was decreased. The differing relationship between bone volume fraction and degree of anisotropy in humans and apes may cause less dense human bone to be more fragile than less dense ape bone.
Topics: Adult; Animals; Anisotropy; Female; Hominidae; Humans; Male; Posture; Spinal Fractures; Thoracic Vertebrae; X-Ray Microtomography
PubMed: 19554642
DOI: 10.1002/ar.20932 -
Journal of Neurosurgery. Spine Mar 2012
Topics: Bone Screws; Female; Humans; Male; Radiography; Spinal Diseases; Thoracic Vertebrae
PubMed: 22150241
DOI: 10.3171/2011.11.SPINE11963 -
British Journal of Hospital Medicine... Nov 2021
Topics: Humans; Laminectomy; Magnetic Resonance Imaging; Spine; Thoracic Vertebrae
PubMed: 34817250
DOI: 10.12968/hmed.2021.0238 -
Medicina 2023Thoracic disc herniation is a rare pathology compared to the rest of the herniated discs. Due to their difficult access to the area of compromise and proximity to the...
Thoracic disc herniation is a rare pathology compared to the rest of the herniated discs. Due to their difficult access to the area of compromise and proximity to the spinal cord they represent a real challenge for the spine surgeon. The objective is to report an atypical case with three symptomatic dorsal disc herniations which required surgical treatment. Surgery was performed in two times with a lapse of 12 months between interventions. It was done a minimally invasive transthoracic decompression and intersomatic arthrodesis without instrumentation. The patient presented good neurological recovery without any serious sequelae.
Topics: Humans; Intervertebral Disc Displacement; Treatment Outcome; Decompression; Thoracic Vertebrae
PubMed: 38117718
DOI: No ID Found -
Neurology India Dec 2005The use of pedicle screw instrumentation in the spine has evolved over the last two decades. The initial use of pedicle screws began in the lumbar spine. As surgeons... (Review)
Review
The use of pedicle screw instrumentation in the spine has evolved over the last two decades. The initial use of pedicle screws began in the lumbar spine. As surgeons have become more comfortable with the complex anatomy required for accurate screw placement, the use of pedicle instrumentation has evolved to include their use in the thoracolumbar and thoracic spine. The impetus behind their increased use is a result of the many advantages that pedicle screw anchorage offers over traditional hook and rod constructs. Improved deformity correction and overall construct rigidity are two important advantages of pedicle screw instrumentation due its three-column control over the spinal elements. First, pedicle screw instrumentation obviates the need to place instrumentation within the spinal canal with its inherent risk of neurologic injury. Second, the placement of pedicle screws is independent of facet or laminar integrity and thus has been extremely useful in traumatic, neoplastic, and degenerative conditions. The benefits of pedicle screws in the thoracic spine has been tempered by the potential for catastrophic neurological or soft tissue injuries due to the close proximity of these structures. The narrow and inconsistent shape of the thoracic pedicles, especially in spinal deformity, makes their placement technically challenging. As a result, surgeons have employed a number of techniques to ensure the safe and efficacious placement of thoracic pedicle screws. Detailed anatomic landmarks used to determine pedicle location, intraoperative imaging including navigation, and neurophysiological monitoring are some of the techniques currently used by surgeons. The implementation of these techniques and a thorough understanding of the complex three-dimensional anatomy have allowed surgeons to successfully place thoracic and thoracolumbar pedicle screws.
Topics: Bone Screws; Diagnostic Imaging; Humans; Monitoring, Intraoperative; Orthopedic Procedures; Thoracic Surgical Procedures; Thoracic Vertebrae; Tomography, X-Ray Computed
PubMed: 16565538
DOI: 10.4103/0028-3886.22613 -
Journal of Spinal Disorders Apr 1993An in vitro model of metastatic lesions in thoracic vertebrae was used to determine if the reduction in vertebral cross-sectional area could be used to predict the...
An in vitro model of metastatic lesions in thoracic vertebrae was used to determine if the reduction in vertebral cross-sectional area could be used to predict the associated strength reduction. Defects, entirely within the trabecular bone, were created in alternating vertebrae of unembalmed human thoracic spines. The adjacent vertebrae were tested intact and served as controls. Defect size was determined as the cross-sectional area of the defect divided by the nominal cross-sectional area of the vertebral body midplane. Vertebrae were tested to failure using combined axial-flexion loads. For each spine, a linear regression was determined between the cross sectional area of the superior endplate and the load at failure for the intact vertebrae. The intact strength of bodies with defects was estimated from this regression. The normalized strength of thoracic vertebrae with trabecular defects was linearly related to the reduction in cross-sectional area (normalized failure load = 1.0-Ad/Ai, r2 = 0.51; Ad = cross-sectional area of defect; and Ai = intact cross-sectional area at midplane). The data suggest that the strength reduction due to lytic defects within the centrum of thoracic vertebrae is proportional to the cross-sectional area of bone resorbed.
Topics: Aged; Aged, 80 and over; Female; Humans; Male; Middle Aged; Stress, Mechanical; Thoracic Vertebrae
PubMed: 8504224
DOI: No ID Found -
Spine Feb 1997This study defined the projection point of the thoracic pedicles on their posterior aspect and its relation to a reliable landmark. It also reported pedicle dimensions...
STUDY DESIGN
This study defined the projection point of the thoracic pedicles on their posterior aspect and its relation to a reliable landmark. It also reported pedicle dimensions based on 43 thoracic spines.
OBJECTIVES
To determine the projection point of the pedicle axis on the posterior aspect of the thoracic spine, quantitatively describe relations of the projection point to some reliable landmarks, and evaluate linear and angular dimensions of the thoracic pedicle.
SUMMARY OF BACKGROUND DATA
Posterior segmental screw fixation is the current standard of internal fixation at the level of the second lumbar vertebrae or below. However, pedicular screw fixation in the thoracic spine, especially in the middle and upper thoracic region, is not common because the small dimensions of the pedicle in this region make screw insertion difficult. More information about pedicle axis projection (not pedicle zone) and its quantitative relationship to some reliable landmarks is essential.
METHODS
Forty-three dry thoracic specimens (516 vertebrae) were obtained for study of the thoracic pedicle. Anatomic evaluation focused on the determination of the projection point of the thoracic pedicle axis on its posterior aspect and the anatomic relationship of this point to the lateral edge of superior facet and the midline of the transverse process. Also, pedicle dimensions, including linear and angular, were measured. The mean, range, and standard deviation were calculated for all of the specimens and for male and female specimens separately.
RESULTS
Sexual difference was found to be significant statistically in more than half of parameters. For T1-T2, the projection point of the pedicle axis was approximately 7-8 mm medial to the lateral edge of the superior facet and 3-4 mm superior to the midline of the transverse process. For T3-T12, this point was 4-5 mm medial to the lateral margin of the facet and 5-8 mm superior to the midline of the transverse process. The transverse angle of the pedicle axis was found to be 30-40 degrees at T1-T2, 20-25 degrees at T3-T11, and 10 degrees at T12.
CONCLUSIONS
This information, in conjunction with preoperative computed tomography evaluation, may enhance our knowledge of transpedicular screw fixation in the thoracic pedicle.
Topics: Adult; Aged; Female; Humans; Male; Middle Aged; Sex Characteristics; Thoracic Vertebrae
PubMed: 9051883
DOI: 10.1097/00007632-199702010-00001 -
Surgical and Radiologic Anatomy : SRA Apr 2012To evaluate the morphologic characteristics of the thoracic pedicle with regard to safe free-hand thoracic pedicle screw placement, based on multi-planar reconstruction...
OBJECTIVE
To evaluate the morphologic characteristics of the thoracic pedicle with regard to safe free-hand thoracic pedicle screw placement, based on multi-planar reconstruction CT images.
METHODS
Thirty adolescent idiopathic scoliosis (AIS) patients who had undergone posterior corrective surgery for major thoracic curve were included in this study. Reconstructed CT axial images at each thoracic vertebra were used to measure: (1) the shortest distance from an entry point to the ventral cortex of the lamina (critical distance), and (2) the distance from the entry point to the tangent of the spinal canal at the medial wall of the pedicle (safe distance). The critical length was defined as the distance between the critical distance and the safe distance. The distance from the entry point to the medial wall breach site (breach distance) was measured on post-operative CT images.
RESULTS
The mean critical distance was 9.3 ± 1.1 mm. The critical distance of vertebrae from different levels was relatively constant, between 8.1 and 10.1 mm. The mean safe distance was 15.2 ± 1.3 mm. The safe distance of vertebrae from different levels was also relatively constant, between 14.5 and 16 mm. The mean critical length was 5.9 ± 1.0 mm. The critical length of vertebrae between T3 and T12 was relatively constant, ranging from 5 to 6.5 mm. The mean breach distance was 12.3 ± 1.3 mm and the each breach always recognized between the critical distance and the safe distance.
CONCLUSIONS
The risk of pedicle medial wall perforation increases as the pedicle probe advances beyond the critical distance of 8-10 mm from the entry point, while it decreases entering into the safe distance at 14.5-16 mm. These parameters were relatively constant even in the most rotated vertebrae at T9 or those with the narrowest pedicle at T7 or T4.
Topics: Adolescent; Bone Screws; Child; Female; Humans; Male; Observer Variation; Orthopedic Procedures; Reference Values; Scoliosis; Thoracic Vertebrae; Tomography, X-Ray Computed
PubMed: 21739245
DOI: 10.1007/s00276-011-0849-z -
Clinical Neurosurgery 1992
Review
Topics: Biomechanical Phenomena; Humans; Spinal Injuries; Thoracic Vertebrae; Weight-Bearing
PubMed: 1537190
DOI: No ID Found