Spinous Process Strength

Shepherd, Duncan E.T.; Leahy, J.C.; Mathias, K. J.; Wilkinson, Steven J.; Hukins, D. W. L.

doi:10.1097/00007632-200002010-00010

Cited by 48 publications

(16 citation statements)

References 23 publications

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“…Similarly, other studies 10 reported an increase in the load transmitted through spinous processes. Although spinous processes may be strong enough to withstand the stresses after implantation, 23 ISP devices may cause gradual erosion at the bone-implant interface under constant stress and motion, thereby increasing the recurrence probability of preoperative symptoms. In addition, the success rate of the outcome of lumbar treatment with an ISP device also depends largely on the bone density 8 and overall lumbar scoliosis 19 of patients.…”

Section: Discussionmentioning

confidence: 99%

Determination of the biomechanical effect of an interspinous process device on implanted and adjacent lumbar spinal segments using a hybrid testing protocol: a finite-element study

Erbulut

Zafarparandeh²,

Hassan³

et al. 2015

SPI

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OBJECT The authors evaluated the biomechanical effects of an interspinous process (ISP) device on kinematics and load sharing at the implanted and adjacent segments. METHODS A 3D finite-element (FE) model of the lumbar spine (L1–5) was developed and validated through comparison with published in vitro study data. Specifically, validation was achieved by a flexible (load-control) approach in 3 main planes under a pure moment of 10 Nm and a compressive follower load of 400 N. The ISP device was inserted between the L-3 and L-4 processes. Intact and implanted cases were simulated using the hybrid protocol in all motion directions. The resultant motion, facet load, and intradiscal pressure after implantation were investigated at the index and adjacent levels. In addition, stress at the bone-implant interface was predicted. RESULTS The hybrid approach, shown to be appropriate for adjacent-level investigations, predicted that the ISP device would decrease the range of motion, facet load, and intradiscal pressure at the index level relative to the corresponding values for the intact spine in extension. Specifically, the intradiscal pressure induced after implantation at adjacent segments increased by 39.7% and by 6.6% at L2–3 and L4–5, respectively. Similarly, facet loads at adjacent segments after implantation increased up to 60% relative to the loads in the intact case. Further, the stress at the bone-implant interface increased significantly. The influence of the ISP device on load sharing parameters in motion directions other than extension was negligible. CONCLUSIONS Although ISP devices apply a distraction force on the processes and prevent further extension of the index segment, their implantation may cause changes in biomechanical parameters such as facet load, intradiscal pressure, and range of motion at adjacent levels in extension.

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Section: Discussionmentioning

confidence: 99%

Determination of the biomechanical effect of an interspinous process device on implanted and adjacent lumbar spinal segments using a hybrid testing protocol: a finite-element study

Erbulut

Zafarparandeh²,

Hassan³

et al. 2015

SPI

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“…[4][5][6]9,10,12 Elderly individuals are often affected by bone fragility even without a definite diagnosis of osteoporosis. Hence, they should be considered at risk for this procedure.…”

Section: Discussionmentioning

confidence: 99%

“…6,11 Consequently, this treatment is contraindicated in patients with osteoporosis. [4][5][6]9,10,12 Additionally, due to the frequent bone mass loss, advanced age (older than 75 years) can be considered a risk factor as well.…”

mentioning

confidence: 99%

Posterior Vertebral Arch Cement Augmentation (Spinoplasty) to Prevent Fracture of Spinous Processes after Interspinous Spacer Implant

Bonaldi

Bertolini

Marrocu

et al. 2011

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE:Interspinous spacers are implanted to treat symptomatic lumbar stenosis. Posterior vertebral element fractures can occur during or after interspinous spacer implants, especially in patients with osteopenia. The purpose of our study was to assess the biomechanical rationale, safety, feasibility, and effectiveness of posterior vertebral arch cement augmentation (spinoplasty) in preventing delayed spinous process fractures after interspinous spacer implants in patients with risk factors for fragility fractures.

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“…Our experimental results indicate that a plate placed between two spinous processes reduces the intervertebral stress. 23 According to Shepherd, et al, 30 the strength of the spinous process is sufficient to withstand the load that is conducted with a flexible fixation device. As noted previously, flexible posterior fixation (for example, with an interspinous plate placed between two spinous processes) can be expected to prevent collapse of the grafted rib and to provide adequate stress to the grafts, which also facilitates solid bone union.…”

Section: Discussionmentioning

confidence: 99%

Use of folded vascularized rib graft in anterior fusion after treatment of thoracic and upper lumbar lesions

Nakamura

Yamano²,

Seki³

et al. 2001

Journal of Neurosurgery: Spine

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✓ For lesions involving the anterior and/or middle column of the spine, an anterior approach is adequate for curetting the lesion and restoring spinal stability. Materials such as autogenous bone grafts, cages with bone chips, some artificial materials, or allografts are used as strut materials. Rib material is usually removed when the anterior approach is conducted for thoracic or thoracolumbar lesions. A rib itself is not rigid enough to support the load, and a bone union is not easily obtained. The purpose of this paper is to describe a method of grafting vascularized rib in folded form to fill the defects left after removal of a spinal lesion. The rib, with the artery and vein at two levels cranial to the involved vertebral body, was isolated from surrounding tissues such as the intercostal nerve, muscles, and pleura. After curetting the lesion, the rib was folded into three or four pieces to a length adequate to fill the defect and inserted as a pedicled vascularized graft. A total of 23 cases, including 14 men and nine women, underwent surgery in which this grafting technique was used. The pathological conditions requiring anterior decompression and fusion were spinal trauma in nine cases, spinal infection in six cases, osteoporotic fracture in seven cases, and spinal metastasis in one case. In all cases a solid bone union was obtained and all infections resolved. With vascularized rib graft folded into three to four pieces, solid bone union can be obtained without use of any other grafted materials even in cases of infection and osteoporosis.

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Spinous Process Strength

Abstract: Specimens with a bone mineral density in the range of 0.263-0.997 g/cm2 failed at a mean load of 339 N when the load was applied through the spinous process hook of a flexible fixation device.

Cited by 48 publications

References 23 publications

Determination of the biomechanical effect of an interspinous process device on implanted and adjacent lumbar spinal segments using a hybrid testing protocol: a finite-element study

Determination of the biomechanical effect of an interspinous process device on implanted and adjacent lumbar spinal segments using a hybrid testing protocol: a finite-element study

Posterior Vertebral Arch Cement Augmentation (Spinoplasty) to Prevent Fracture of Spinous Processes after Interspinous Spacer Implant

Use of folded vascularized rib graft in anterior fusion after treatment of thoracic and upper lumbar lesions

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