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Tommy Hansson - One of the best experts on this subject based on the ideXlab platform.
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Effect of Strain Rate and Bone Mineral on the Structural Properties of the Human Anterior Longitudinal Ligament
Spine, 1994Co-Authors: P. Neumann, Tony S. Keller, Lars Ekström, Tommy HanssonAbstract:The effect of strain rate and bone mineral content on the biomechanical properties of the human lumbar Anterior Longitudinal Ligament-bone complex was studied. Tensile structural properties were determined for 54 such preparations subjected to distraction rates ranging from 0.1–230 mm/sec. The ultim
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aging vertebral density and disc degeneration alter the tensile stress strain characteristics of the human Anterior Longitudinal Ligament
Journal of Orthopaedic Research, 1994Co-Authors: P. Neumann, Tony S. Keller, L Perry, L Ekstrom, Tommy HanssonAbstract:The mechanical properties of the human lumbar Anterior Longitudinal Ligament were investigated, and the influence of aging, disc degeneration, and vertebral bone density on these properties was determined. Tensile mechanical properties of the vertebra-Anterior Longitudinal Ligament-vertebra complex were determined for 16 segments from cadavera of individuals who had been 21–79 years old (mean, 52.1 years) at the time of death. Regional strain patterns associated with three sites across the width and three sites along the length of the Anterior Longitudinal Ligament were measured with use of a video-based motion analysis system. In the young, normal Anterior Longitudinal Ligament, the elastic moduli of the insertion and substance regions of the Ligament were similar (approximately 500 MPa). During aging (21–79 years), the elastic modulus of the substance region increased 2-fold, whereas the elastic modulus of the insertion decreased 3-fold; this resulted in an approximately 5-fold difference in elastic modulus between these regions in the older spine. The strength of the bone-Ligament complex decreased approximately 2-fold (from 29 to 13 MPa) over this same age range. The outer portion of the Anterior Longitudinal Ligament consistently had the highest peak tensile strains (11.8 ± 2.7%) in all of the specimens examined. Preparations with nondegenerated discs and high bone density were significantly stronger (66%) and failed in the Ligament substance; in contrast, segments from older individuals with degenerated discs and lower bone density failed in the Ligament insertion regions.
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Structural properties of the Anterior Longitudinal Ligament. Correlation with lumbar bone mineral content.
Spine, 1993Co-Authors: P. Neumann, Tony S. Keller, Lars Ekström, E Hult, Tommy HanssonAbstract:The relationship between the amount of bone in the lumbar spine and Ligamentous properties has not been studied. This article reports the tensile structural properties of bone-Ligament-bone preparations of the Anterior Longitudinal Ligament from 15 human lumbar spine segments. Significant correlations were found between the vertebral bone mineral content expressed as BMC (g/cm) and BMA (g/cm2) and BMD (g/cm3) and the structural properties of the vertebral bone-Anterior Longitudinal Ligament-bone complex determined at yield and failure. These findings suggest that the amount of bone tissue in the spine may be functionally related to structural properties of the spinal Ligaments.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, Lena Ekstrom, L Perry, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, L Perry, L Ekstrom, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.
P. Neumann - One of the best experts on this subject based on the ideXlab platform.
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Effect of Strain Rate and Bone Mineral on the Structural Properties of the Human Anterior Longitudinal Ligament
Spine, 1994Co-Authors: P. Neumann, Tony S. Keller, Lars Ekström, Tommy HanssonAbstract:The effect of strain rate and bone mineral content on the biomechanical properties of the human lumbar Anterior Longitudinal Ligament-bone complex was studied. Tensile structural properties were determined for 54 such preparations subjected to distraction rates ranging from 0.1–230 mm/sec. The ultim
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aging vertebral density and disc degeneration alter the tensile stress strain characteristics of the human Anterior Longitudinal Ligament
Journal of Orthopaedic Research, 1994Co-Authors: P. Neumann, Tony S. Keller, L Perry, L Ekstrom, Tommy HanssonAbstract:The mechanical properties of the human lumbar Anterior Longitudinal Ligament were investigated, and the influence of aging, disc degeneration, and vertebral bone density on these properties was determined. Tensile mechanical properties of the vertebra-Anterior Longitudinal Ligament-vertebra complex were determined for 16 segments from cadavera of individuals who had been 21–79 years old (mean, 52.1 years) at the time of death. Regional strain patterns associated with three sites across the width and three sites along the length of the Anterior Longitudinal Ligament were measured with use of a video-based motion analysis system. In the young, normal Anterior Longitudinal Ligament, the elastic moduli of the insertion and substance regions of the Ligament were similar (approximately 500 MPa). During aging (21–79 years), the elastic modulus of the substance region increased 2-fold, whereas the elastic modulus of the insertion decreased 3-fold; this resulted in an approximately 5-fold difference in elastic modulus between these regions in the older spine. The strength of the bone-Ligament complex decreased approximately 2-fold (from 29 to 13 MPa) over this same age range. The outer portion of the Anterior Longitudinal Ligament consistently had the highest peak tensile strains (11.8 ± 2.7%) in all of the specimens examined. Preparations with nondegenerated discs and high bone density were significantly stronger (66%) and failed in the Ligament substance; in contrast, segments from older individuals with degenerated discs and lower bone density failed in the Ligament insertion regions.
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Structural properties of the Anterior Longitudinal Ligament. Correlation with lumbar bone mineral content.
Spine, 1993Co-Authors: P. Neumann, Tony S. Keller, Lars Ekström, E Hult, Tommy HanssonAbstract:The relationship between the amount of bone in the lumbar spine and Ligamentous properties has not been studied. This article reports the tensile structural properties of bone-Ligament-bone preparations of the Anterior Longitudinal Ligament from 15 human lumbar spine segments. Significant correlations were found between the vertebral bone mineral content expressed as BMC (g/cm) and BMA (g/cm2) and BMD (g/cm3) and the structural properties of the vertebral bone-Anterior Longitudinal Ligament-bone complex determined at yield and failure. These findings suggest that the amount of bone tissue in the spine may be functionally related to structural properties of the spinal Ligaments.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, Lena Ekstrom, L Perry, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, L Perry, L Ekstrom, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.
Tony S. Keller - One of the best experts on this subject based on the ideXlab platform.
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Effect of Strain Rate and Bone Mineral on the Structural Properties of the Human Anterior Longitudinal Ligament
Spine, 1994Co-Authors: P. Neumann, Tony S. Keller, Lars Ekström, Tommy HanssonAbstract:The effect of strain rate and bone mineral content on the biomechanical properties of the human lumbar Anterior Longitudinal Ligament-bone complex was studied. Tensile structural properties were determined for 54 such preparations subjected to distraction rates ranging from 0.1–230 mm/sec. The ultim
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aging vertebral density and disc degeneration alter the tensile stress strain characteristics of the human Anterior Longitudinal Ligament
Journal of Orthopaedic Research, 1994Co-Authors: P. Neumann, Tony S. Keller, L Perry, L Ekstrom, Tommy HanssonAbstract:The mechanical properties of the human lumbar Anterior Longitudinal Ligament were investigated, and the influence of aging, disc degeneration, and vertebral bone density on these properties was determined. Tensile mechanical properties of the vertebra-Anterior Longitudinal Ligament-vertebra complex were determined for 16 segments from cadavera of individuals who had been 21–79 years old (mean, 52.1 years) at the time of death. Regional strain patterns associated with three sites across the width and three sites along the length of the Anterior Longitudinal Ligament were measured with use of a video-based motion analysis system. In the young, normal Anterior Longitudinal Ligament, the elastic moduli of the insertion and substance regions of the Ligament were similar (approximately 500 MPa). During aging (21–79 years), the elastic modulus of the substance region increased 2-fold, whereas the elastic modulus of the insertion decreased 3-fold; this resulted in an approximately 5-fold difference in elastic modulus between these regions in the older spine. The strength of the bone-Ligament complex decreased approximately 2-fold (from 29 to 13 MPa) over this same age range. The outer portion of the Anterior Longitudinal Ligament consistently had the highest peak tensile strains (11.8 ± 2.7%) in all of the specimens examined. Preparations with nondegenerated discs and high bone density were significantly stronger (66%) and failed in the Ligament substance; in contrast, segments from older individuals with degenerated discs and lower bone density failed in the Ligament insertion regions.
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Structural properties of the Anterior Longitudinal Ligament. Correlation with lumbar bone mineral content.
Spine, 1993Co-Authors: P. Neumann, Tony S. Keller, Lars Ekström, E Hult, Tommy HanssonAbstract:The relationship between the amount of bone in the lumbar spine and Ligamentous properties has not been studied. This article reports the tensile structural properties of bone-Ligament-bone preparations of the Anterior Longitudinal Ligament from 15 human lumbar spine segments. Significant correlations were found between the vertebral bone mineral content expressed as BMC (g/cm) and BMA (g/cm2) and BMD (g/cm3) and the structural properties of the vertebral bone-Anterior Longitudinal Ligament-bone complex determined at yield and failure. These findings suggest that the amount of bone tissue in the spine may be functionally related to structural properties of the spinal Ligaments.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, Lena Ekstrom, L Perry, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, L Perry, L Ekstrom, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.
Juan S. Uribe - One of the best experts on this subject based on the ideXlab platform.
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Release of Anterior Longitudinal Ligament in Setting of Unfavorable Vascular Anatomy for Anterior Column Realignment—Technical Note: 2-Dimensional Operative Video
Operative neurosurgery (Hagerstown Md.), 2019Co-Authors: Jakub Godzik, Juan S. Uribe, Corey T. Walker, Alexander C. Whiting, Randall J. Hlubek, Jay D. TurnerAbstract:Anterior column realignment (ACR) with Anterior Longitudinal Ligament (ALL) release from a lateral transpsoas approach is increasingly being used as a minimally invasive technique to restore lordosis. Safe execution requires a plane between the ALL and the Anterior vasculature. An unfavorable plane on preoperative imaging is a contraindication to using the technique. We describe a patient undergoing multistage minimally invasive correction of a flat-back deformity who had an unfavorable plane between the ALL and vasculature at L4-5. Patient consent was provided, and Institutional Review Board approval was not required. To safely complete the ALL release and ACR, we elected to sharply incise the lateral aspect of the Ligament at L4-5 with direct control of the vessels during the Anterior approach for an L5-S1 Anterior lumbar interbody fusion. We then moved to the lateral transpsoas approach and used controlled distraction techniques to complete the ALL release and then to complete the ACR in a standard fashion. We ultimately achieved excellent realignment with correction of the patient's flat-back deformity using minimally invasive surgical techniques while minimizing vascular risk. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.
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Anterior Longitudinal Ligament Release From the Minimally Invasive Lateral Retroperitoneal Transpsoas Approach: Technical Note.
Operative neurosurgery (Hagerstown Md.), 2016Co-Authors: Joshua M. Beckman, Nicola Marengo, Gisela Murray, Konrad Bach, Juan S. UribeAbstract:BACKGROUND The technique for minimally invasive Anterior Longitudinal Ligament release is a major advancement in lateral access surgery. This method provides hypermobility of lumbar segments to allow for aggressive lordosis restoration while maintaining the benefits of indirect decompression and minimally invasive access. OBJECTIVE To provide video demonstration of the lateral retroperitoneal transpsoas approach with Anterior Longitudinal Ligament sectioning. METHODS A detailed surgical technique of the minimally invasive Anterior column release is described and illustrated in an elderly patient with adult spinal deformity and low back pain (visual analog scale, 8 of 10) refractory to conservative measures. The 3-foot standing radiographs demonstrated a lumbar lordosis of 54.4°, pelvic incidence of 63.7°, and pelvic tilt of 17.5°. Computed tomography and magnetic resonance imaging showed generalized lumbar spondylosis and degenerative disc changes from L2 to L5. RESULTS The patient underwent a multilevel minimally invasive deformity correction with an Anterior Longitudinal Ligament release at the L3/L4 level through the lateral retroperitoneal transpsoas approach. Lumbar lordosis increased from 54.4° to 77° with a global improvement in sagittal vertical axis from 4.37 cm to 0 cm. Total blood loss was less than 25 mL, and there were no major neurological or vascular complications. CONCLUSION The Anterior Longitudinal Ligament release using the minimally invasive lateral approach allows for deformity correction without the morbidity and blood loss encountered by traditional open posterior approaches. However, the risk of major vascular/visceral complication warrants only experts in minimally invasive lateral surgery to attempt this technique.
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finite element analysis of lordosis restoration with Anterior Longitudinal Ligament release and lateral hyperlordotic cage placement
European Spine Journal, 2015Co-Authors: Juan S. Uribe, Joshua M. Beckman, Jeffrey E Harris, Alexander W L Turner, Gregory M Mundis, Behrooz A AkbarniaAbstract:Purpose Restoring sagittal alignment is an important factor in the treatment of spinal deformities. Recent investigations have determined that releasing the Anterior Longitudinal Ligament (ALL) and placing hyperlordotic cages can increase lordosis, while minimizing need for 3 column osteotomies. The influences of parameters such as cage height and angle have not been determined. Finite element analysis was employed to assess the extent of lordosis achievable after placement of different sized lordotic cages.
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Finite element analysis of lordosis restoration with Anterior Longitudinal Ligament release and lateral hyperlordotic cage placement.
European spine journal : official publication of the European Spine Society the European Spinal Deformity Society and the European Section of the Cerv, 2015Co-Authors: Juan S. Uribe, Jeffrey E Harris, Alexander W L Turner, Gregory M Mundis, J M Beckman, Behrooz A AkbarniaAbstract:Restoring sagittal alignment is an important factor in the treatment of spinal deformities. Recent investigations have determined that releasing the Anterior Longitudinal Ligament (ALL) and placing hyperlordotic cages can increase lordosis, while minimizing need for 3 column osteotomies. The influences of parameters such as cage height and angle have not been determined. Finite element analysis was employed to assess the extent of lordosis achievable after placement of different sized lordotic cages. A 3-dimensional model of a L3-4 segment was used. Disc distraction was simulated by inserting interbody cages mid-body in the disc space. Analyses were performed in the following conditions: (1) intact, (2) ALL release, (3) ALL release + facetectomy, and (4) ALL release + posterior column osteotomy. Changes in segmental lordosis, disc height, foraminal height, and foraminal area were measured. After ALL resection and insertion of hyperlordotic cages, lordosis was increased in all cases. The lordosis achieved by the shorter cages was less due to posterior disc height maintained by the facet joints. A facetectomy increased segmental lordosis, but led to contact between the spinous processes. For some configurations, a posterior column osteotomy was required if the end goal was to match cage angle to intradiscal angle. Increased segmental lumbar lordosis is achievable with hyperlordotic cages after ALL resection. Increased cage height tended to increase the amount of lordosis achieved, although in some cases additional posterior bone resection was required to maximize lordosis. Further studies are needed to evaluate the impact on regional lumbar lordosis.
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Early Outcomes of Minimally Invasive Anterior Longitudinal Ligament Release for Correction of Sagittal Imbalance in Patients with Adult Spinal Deformity
TheScientificWorldJournal, 2012Co-Authors: Armen R. Deukmedjian, Elias Dakwar, Amir Ahmadian, Donald A. Smith, Juan S. UribeAbstract:The object of this study was to evaluate a novel surgical technique in the treatment of adult degenerative scoliosis and present our early experience with the minimally invasive lateral approach for Anterior Longitudinal Ligament release to provide lumbar lordosis and examine its impact on sagittal balance. Methods. All patients with adult spinal deformity (ASD) treated with the minimally invasive lateral retroperitoneal transpsoas interbody fusion (MIS LIF) for release of the Anterior Longitudinal Ligament were examined. Patient demographics, clinical data, spinopelvic parameters, and outcome measures were recorded. Results. Seven patients underwent release of the Anterior Longitudinal Ligament (ALR) to improve sagittal imbalance. All cases were split into Anterior and posterior stages, with mean estimated blood loss of 125 cc and 530 cc, respectively. Average hospital stay was 8.3 days, and mean follow-up time was 9.1 months. Comparing pre- and postoperative 36′′ standing X-rays, the authors discovered a mean increase in global lumbar lordosis of 24 degrees, increase in segmental lumbar lordosis of 17 degrees per level of ALL released, decrease in pelvic tilt of 7 degrees, and decrease in sagittal vertical axis of 4.9 cm. At the last followup, there was a mean improvement in VAS and ODI scores of 26.2% and 18.3%. Conclusions. In the authors’ early experience, release of the Anterior Longitudinal Ligament using the minimally invasive lateral retroperitoneal transpsoas approach may be a feasible alternative in correcting sagittal deformity.
Dan M. Spengler - One of the best experts on this subject based on the ideXlab platform.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, Lena Ekstrom, L Perry, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.
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Mechanical properties of the human lumbar Anterior Longitudinal Ligament
Journal of Biomechanics, 1992Co-Authors: P. Neumann, Tony S. Keller, Tommy Hansson, L Perry, L Ekstrom, Dan M. SpenglerAbstract:Abstract A new technique incorporating a motion analysis system and a materials testing machine was used to investigate regional differences in the tensile mechanical properties of the lumbar spine Anterior Longitudinal Ligament (ALL). Bone-ALL-bone specimens were prepared from young human cadaveric motion segments with no disc or bony pathology. Each specimen was distracted until failure at a constant crosshead displacement rate of 2.5 mm s −1 (approximately 1.0% strain per second). Strains were evaluated from digitized video recordings of markers attached to the ALL at 12 sites along its length and width, including the Ligament substance and insertions. The ‘overall’ strain in the Ligament was calculated from the outermost pairs of markers along the Ligament length. The average tensile strength, the ‘overall’ tensile modulus and the ‘overall’ strain of the ALL at failure were 27.4 MPa (S.D. 5.9), 759 MPa (S.D. 336) and 4.95% (S.D. 1.51), respectively. Large and significant variations in the strains were present along the width and length of the ALL. Peak substance strains were over twofold greater than peak strains at the Ligament insertion sites, whereas across the Ligament width, peak strains in the outer portion of the Ligament were over 40% greater than in the central region. Failure consistently occurred in the Ligament mid-substance and ultimate strains at the Ligament failure site averaged 12.1% (S.D. 2.3). These results indicate that the strains are highly nonuniform in the normal ALL.