Effects of Bone Mineral Density on Pedicle Screw Fixation

Halvorson, Thomas L.; Kelley, Lee Ann; Thomas, Kevin A.; Whitecloud, Thomas S.; Cook, Stephen D.

doi:10.1097/00007632-199411000-00008

Cited by 567 publications

(360 citation statements)

References 0 publications

Supporting

Mentioning

336

Contrasting

Unclassified

Order By: Relevance

“…Another aspect of the osteopenic model is that the bone mineral density in sheep is different from that of humans, which might influence screw osseointegration. However, when BMD is assessed in the adult spine of a human without osteoporosis the 'at risk' value is decreased by about 25%, which corresponds to that observed in our sheep model (22-25%) [9,34]. Finally, current results suggest that this kind of model is suitable for studying osseointegration and fixation in the osteoporotic spine.…”

Section: Discussionsupporting

confidence: 81%

See 1 more Smart Citation

In vivo preclinical evaluation of the influence of osteoporosis on the anchorage of different pedicle screw designs

et al. 2011

View full text Add to dashboard Cite

show abstract

Section: Discussionsupporting

confidence: 81%

“…Anchoring the screws to the bone is crucial for the success of these implants. Screw loosening was particularly evident during the instrumentation of vertebral bodies with low mineral density or patients with osteoporosis [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

In vivo preclinical evaluation of the influence of osteoporosis on the anchorage of different pedicle screw designs

et al. 2011

View full text Add to dashboard Cite

show abstract

“…In some patients, surgical treatment is unavoidable. An osteoporotic spine presents a significant challenge for a spinal surgeon to manage [7,14].…”

Section: Introductionmentioning

confidence: 99%

Polymethylmethacrylate augmentation of the pedicle screw: the cement distribution in the vertebral body

Chang

et al. 2011

Eur Spine J

View full text Add to dashboard Cite

Many studies have proven that the polymethylmethacrylate (PMMA) augmentation of the pedicle screw can significantly increase stiffness and strength of spinal fixation. Some major complications have also been reported. However, there are no reports discussing cement distribution and its morphology in the osteoporotic vertebral body, which is critical in the analysis of the biomechanical strength of the pedicle screw and the risk of cement leakage after pedicle screw augmentation. In this study, we used computed tomography (CT) to evaluate the cement distribution in the osteoporotic vertebral body after PMMA augmentation of a pedicle screw and to analyze the factors leading to cement leakage. Two groups of patients were studied. Group A consisted 25 osteoporotic patients (mean age of 73 years) with spinal instrumentation who had a total of 145 pedicle screws and cement augmentation with biopsy needles. Group B consisted of 23 osteoporotic patients (mean age of 74.6 years) with spinal instrumentation who had a total of 125 cannulated pedicle screws with cement augmentation. All patients had CT evaluation of the cement distribution in the vertebral body after the surgery. The cement distribution in the vertebrae was divided into four zones in the axial CT view: anterior onethird, middle third, and posterior third of vertebral body, and the pedicle. The morphology of the cement distribution around the pedicle screw was defined as scattered type or concentrate type. The leakage pattern was divided to anterior-lateral, posterior-lateral, and canal leakage. The correlations among bone mineral density (BMD), the cement leakage rate, and cement distribution morphology were also analyzed. The results showed that most augmented pedicle screws had cement extension into three of the four zones of the vertebral body (66.3%), followed by two zones (20%), all four zones (11.5%), and only one zone (2.2%). Overall, 123 screws (84.8%) in Group A and 108 screws (86.4%) in Group B had cement concentrate type distribution. The cement leakage rate in Group A is 18.3% and 13.6% in Group B. Patients with a BMD \0.6 g/cm 2 had significantly higher rates of cement leakage and tended toward a scattered cement distribution. There was only one patient who had a symptomatic leakage (sciatica) in Group B. We concluded that the cement distribution after pedicle screw augmentation with biopsy needle or cannulated screw technique was mostly localized in three zones of the vertebral body, and patients with lower BMD had a higher risk of cement leakage and scattered cement distribution.

show abstract

“…Hooks in a claw configuration spanning two vertebral levels can augment the holding grip of the construct. Experimental work indicates that transpedicular screw axial pull-out is correlated to the vertebral bone mineral density [21,58,99,131]. Triangulation of pedicle screws apparently resists axially directed screw pull-out [54,55].…”

Section: Options For Instrumentationmentioning

confidence: 99%

“…Augmentation of transpedicle screw fixation in osteoporotic patients using polymethylmethacrylate has been accepted as a sound technical principle [22,85,96,131]. A combination of pedicle screw and laminar hooks will provide the greatest resistance to pull-out forces [7,17,58,61,92] (Fig. 11).…”

Section: Options For Instrumentationmentioning

confidence: 99%

Principles of management of osteometabolic disorders affecting the aging spine

Hadjipavlou

Katonis

Tzermiadianos

et al. 2003

European Spine Journal

View full text Add to dashboard Cite

Osteoporosis is the most common contributing factor of spinal fractures, which characteristically are not generally known to produce spinal cord compression symptoms. Recently, an increasing number of medical reports have implicated osteoporotic fractures as a cause of serious neurological deficit and painful disabling spinal deformities. This has been corroborated by the present authors as well. These complications are only amenable to surgical management, requiring instrumentation. Instrumenting an osteoporotic spine, although a challenging task, can be accomplished if certain guidelines for surgical techniques are respected. Neurological deficits respond equally well to an anterior or posterior decompression, provided this is coupled with multisegmental fixation of the construct. With the steady increase in the elderly population, it is anticipated that the spine surgeon will face serious complications of osteoporotic spines more frequently. With regard to surgery, however, excellent correction of deformities can be achieved, by combining anterior and posterior approaches. Paget's disease of bone (PD) is a non-hormonal osteometabolic disorder and the spine is the second most commonly affected site. About one-third of patients with spinal involvement exhibit symptoms of clinical stenosis. In only 12-24% of patients with PD of the spine is back pain attributed solely to PD, while in the majority of patients, back pain is either arthritic in nature or a combination of a pagetic process and coexisting arthritis. In this context, one must be certain before attributing low back pain to PD exclusively, and antipagetic medical treatment alone may be ineffective. Neural element dysfunction may be attributed to compressive myelopathy by pagetic bone overgrowth, pagetic intraspinal soft tissue overgrowth, ossification of epidural fat, platybasia, spontaneous bleeding, sarcomatous degeneration and vertebral fracture or subluxation. Neural dysfunction can also result from spinal ischemia when blood is diverted by the so-called "arterial steal syndrome". Because the effectiveness of pharmacologic treatment for pagetic spinal stenosis has been clearly demonstrated, surgical decompression should only be instituted after failure of antipagetic medical treatment. Surgery is indicated as a primary treatment when neural compression is secondary to pathologic fractures, dislocations, spontaneous epidural hematoma, syringomyelia, platybasia, or sarcomatous transformation. Five classes of drugs are available for the treatment of PD. Bisphosphonates are the most popular antipagetic drug and several forms have been investigated. Keywords

show abstract

Effects of Bone Mineral Density on Pedicle Screw Fixation

Cited by 567 publications

References 0 publications

In vivo preclinical evaluation of the influence of osteoporosis on the anchorage of different pedicle screw designs

In vivo preclinical evaluation of the influence of osteoporosis on the anchorage of different pedicle screw designs

Polymethylmethacrylate augmentation of the pedicle screw: the cement distribution in the vertebral body

Principles of management of osteometabolic disorders affecting the aging spine

Contact Info

Product

Resources

About