Biochemistry of fusion mass consolidation in the sheep spine

Slater, R.Giuseppi; Nagel, Donald A.; Smith, R. Lane

doi:10.1002/jor.1100060118

Cited by 17 publications

(6 citation statements)

References 30 publications

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“…Animal models that have been used to study bone formation during fusion utilizing radiography, load measurement techniques, and histology2, 3, 9, 21, 22 have provided a preliminary understanding of the relationship between loading, bone healing, and remodeling in the spine. However, loading conditions in these models are very different than those on the human spine, making it difficult to extrapolate these measurements to loads expected in patients during normal activities.…”

Section: Discussionmentioning

confidence: 99%

In vivo strain measurements from hardware and lamina during spine fusion

2005

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Currently, spine fusion is determined using radiography and clinical evaluation. There are discrepancies between radiographic evidence and direct measurements of fusion, such as operative exploration and biomechanical or histological measurements. In order to facilitate the rapid return of patients to normal activities, a monitoring technique to accurately detect fusion in vivo and to prevent overload during the postoperative period would be useful. The objectives of this study were to develop an implantable monitoring system consisting of CPC-coated strain gauges and a radio transmitter to detect the onset of fusion and measure strain during postsurgical activities. A patient underwent anterior release and fusion, followed by posterior instrumentation and fusion with segmental spinal instrumentation. Four strain gauges were placed during surgery. One was attached to the left-side rod and one to each of the lamina at T9, T10, and T11. An externally powered implanted radio transmitter attached to the gauges was placed in a subcutaneous pouch. Strains were monitored weekly and tabulated during various activities for 7 months. Peak strains during twisting and bending were tabulated to detect the onset of fusion. Strains were also recorded during activities such as climbing off an examination table, rising from a chair, and climbing stairs. Strains collected from the left rod indicated that, immediately postoperatively, it was loaded at acceptable levels. The largest and most consistent strain changes measured from the lamina were recorded during twisting.

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Section: Discussionmentioning

confidence: 99%

In vivo strain measurements from hardware and lamina during spine fusion

2005

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“…Sheep spines were used to study the initial stabilizing effect of spinal implants in cervical and lumbar segments [10,11]. Furthermore, the similar histomorphology of the lumbar intervertebral disc (IVD) and good results in fusion techniques made the ovine species also a good model for in vivo studies.…”

Section: Introductionmentioning

confidence: 99%

A novel finite element model of the ovine lumbar intervertebral disc with anisotropic hyperelastic material properties

et al. 2017

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The Ovine spine is an accepted model to investigate the biomechanical behaviour of the human lumbar one. Indeed, the use of animal models for in vitro studies is necessary to investigate the mechanical behaviour of biological tissue, but needs to be reduced for ethical and social reasons. The aim of this study was to create a finite element model of the lumbar intervertebral disc of the sheep that may help to refine the understanding of parallel in vitro experiments and that can be used to predict when mechanical failure occurs. Anisotropic hyperelastic material properties were assigned to the annulus fibrosus and factorial optimization analyses were performed to find out the optimal parameters of the ground substance and of the collagen fibers. For the ground substance of the annulus fibrosus the investigation was based on experimental data taken from the literature, while for the collagen fibers tensile tests on annulus specimens were conducted. Flexibility analysis in flexion-extension, lateral bending and axial rotation were conducted. Different material properties for the anterior, lateral and posterior regions of the annulus were found. The posterior part resulted the stiffest region in compression whereas the anterior one the stiffest region in tension. Since the flexibility outcomes were in a good agreement with the literature data, we considered this model suitable to be used in conjunction with in vitro and in vivo tests to investigate the mechanical behaviour of the ovine lumbar disc.

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“…Aside from calf spines, those of pigs [2,3,21,28,30], goats [5, 38,64], sheep [1,27,46,51], and canines [8,22,24,25,48,52,63,66] have been used for biomechanical experiments. Calf spines are the most widely used specimens as they appear to approximate most closely the properties of the human spine [7].…”

Section: Introductionmentioning

confidence: 99%

Load-displacement properties of the thoracolumbar calf spine: Experimental results and comparison to known human data

et al. 1997

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The availability of human cadaveric spine specimens for in vitro tests is limited and the risk of infection is now of vital concern. As an alternative or supplement, calf spines have been used as models for human spines, in particular to evaluate spinal implants. However, neither qualitative nor quantitative biomechanical data on calf spines are available for comparison with data on human specimens. The purpose of this study was to determine the fundamental biomechanical properties of calf spines and to compare them with existing data from human specimens. Range of motion, neutral zone, and stiffness properties of thoracolumbar calf spines (T6-L6) were determined under pure moment loading in flexion and extension, axial left/right rotation and right/left lateral bending. Biomechanical similarities were observed between the calf and reported human data, most notably in axial rotation and lateral bending. Range of motion in the lumbar spine in flexion and extension was somewhat less in the calf than that typically reported for the human, though still within the range. These results suggest that the calf spine can be considered on a limited basis as a model for the human spine in certain in vitro tests.

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Biochemistry of fusion mass consolidation in the sheep spine

Cited by 17 publications

References 30 publications

In vivo strain measurements from hardware and lamina during spine fusion

In vivo strain measurements from hardware and lamina during spine fusion

A novel finite element model of the ovine lumbar intervertebral disc with anisotropic hyperelastic material properties

Load-displacement properties of the thoracolumbar calf spine: Experimental results and comparison to known human data

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