Influence of Screw Positioning in a New Anterior Spine Fixator on Implant Loosening in Osteoporotic Vertebrae

Reinhold, M.; Schwieger, Karsten; Goldhahn, Jörg; Linke, Berend; Knop, C.; Blauth, M.

doi:10.1097/01.brs.0000199894.63450.70

Cited by 39 publications

(16 citation statements)

References 64 publications

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“…This trend can be explained as a result of the superior biomechanical properties of angular stable plate or rod systems when compared with conventional implants [34,52]. In this context, the relevance of newly developed screw designs and their configuration within the VB have to be considered as well [33,72,75]. New expandable anterior devices can be implanted via thoracoscopic approaches; thus, reducing the perioperative morbidity and pain with better lung function as compared to conventional thoracotomies [8,15,50,65].…”

Section: Discussionmentioning

confidence: 99%

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

et al. 2010

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The second, internet-based multicenter study (MCSII) of the Spine Study Group of the German Association of Trauma Surgery (Deutsche Gesellschaft für Unfallchirurgie) is a representative patient collection of acute traumatic thoracolumbar (T1-L5) injuries. The MCSII results are an update of those obtained with the first multicenter study (MCSI) more than a decade ago. The aim of the study was to assess and bring into focus: the (1) epidemiologic data, (2) surgical and radiological outcome, and (3) 2-year follow-up (FU) results of these injuries.According to the Magerl/AO classification, there were 424 (57.8%) compression fractures (A type), 178 (24.3%) distractions injuries (B type), and 131 (17.9%) rotational injuries (C type). B and C type injuries carried a higher risk for neurological deficits, concomitant injuries, and multiple vertebral fractures. The level of injury was located at the thoracolumbar junction (T11-L2) in 67.0% of the case. 380 (51.8%) patients were operated on by posterior stabilization and instrumentation alone (POSTERIOR), 34 (4.6%) had an anterior procedure (ANTERIOR), and 319 (43.5%)

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Section: Discussionmentioning

confidence: 99%

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

et al. 2010

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“…Many biomechanical studies have demonstrated that pedicle screw fixation is highly correlated with BMD [27]. The screw-bone interface is a dynamic structure with differing mechanical characteristics in different portions of the implant surface.…”

Section: Discussionmentioning

confidence: 99%

“…Pedicle screw instrumentation is one of the most commonly used and rapidly growing forms of stabilization for spinal fusion. Transpedicular fixation, however, can be very challenging in the osteoporotic spine as mechanical stability of the pedicle screws is determined by bone mineral density (BMD) [9,27]. In addition, poor rigidity of the bone-screw contact can lead to loosening of the implant in osteoporotic patients.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical and histological evaluation of an expandable pedicle screw in osteoporotic spine in sheep

Wan

Lei

et al. 2010

Eur Spine J

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Transpedicular fixation can be challenging in the osteoporotic spine as reduced bone mineral density compromises the mechanical stability of the pedicle screw. Here, we sought to investigate the biomechanical and histological properties of stabilization of expandable pedicle screw (EPS) in the osteoporotic spine in sheep. EPSs and standard pedicle screws, SINO screws, were inserted on the vertebral bodies in four female ovariectomized sheep. Pull-out and cyclic bending resistance test were performed to compare the holding strength of these pedicle screws. High-resolution micro-computed tomography (CT) was performed for three-dimensional image reconstruction. We found that the EPSs provided a 59.6% increase in the pull-out strength over the SINO screws. Moreover, the EPSs withstood a greater number of cycles or load with less displacement before loosening. Micro-CT image reconstruction showed that the tissue mineral density, bone volume fraction, bone surface/bone volume ratio, trabecular thickness, and trabecular separation were significantly better in the expandable portion of the EPSs than those in the anterior portion of the SINO screws (P \ 0.05). Furthermore, the trabecular architecture in the screw-bone interface was denser in the expandable portion of the EPS than that in the anterior portion of the SINO screw. Histologically, newly formed bone tissues grew into the center of EPS and were in close contact with the EPS. Our results show that the EPS demonstrates improved biomechanical and histological properties over the standard screw in the osteoporotic spine. The EPS may be of value in treating patients with osteoporosis and warrants further clinical studies.

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“…It is to be expected that triangulated double screw/double rod systems will achieve higher pullout strength than single rod/single screw systems, as several studies showed [30,37,[40][41][42]44]. A two-rod or twoscrew system however, has a high metal load for the patient and, especially in the surgery of spinal deformities in children with small and dyplastic vertrebrae, is more difficult and sometimes impossible to implant.…”

Section: Discussionmentioning

confidence: 99%

“…Like the Kaneda anterior spinal system [21], also the MACS TL twin screw device [37,41] and the MACS TL polyaxial screw XL device [42] have a two screw design with specific angles of the screws to each other in one vertebra. It is to be expected that triangulated double screw/double rod systems will achieve higher pullout strength than single rod/single screw systems, as several studies showed [30,37,[40][41][42]44].…”

Section: Discussionmentioning

confidence: 99%

Pullout strength of anterior spinal instrumentation: a product comparison of seven screws in calf vertebral bodies

et al. 2007

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A lot of new implant devices for spine surgery are coming onto the market, in which vertebral screws play a fundamental role. The new screws developed for surgery of spine deformities have to be compared to established systems. A biomechanical in vitro study was designed to assess the bone-screw interface fixation strength of seven different screws used for correction of scoliosis in spine surgery. The objectives of the current study were twofold: (1) to evaluate the initial strength at the bone-screw interface of newly developed vertebral screws (Universal Spine System II) compared to established systems (product comparison) and (2) to evaluate the influence of screw design, screw diameter, screw length and bone mineral density on pullout strength. Fifty-six calf vertebral bodies were instrumented with seven different screws (USS II anterior 8.0 mm, USS II posterior 6.2 mm, KASS 6.25 mm, USS II anterior 6.2 mm, USS II posterior 5.2 mm, USS 6.0 mm, USS 5.0 mm). Bone mineral density (BMD) was determined by quantitative computed tomography (QCT). Failure in axial pullout was tested using a displacement-controlled universal test machine. USS II anterior 8.0 mm showed higher pullout strength than all other screws. The difference constituted a tendency (P = 0.108) when compared to USS II posterior 6.2 mm (+19%) and was significant in comparison to the other screws (+30 to +55%, P < 0.002). USS II posterior 6.2 mm showed significantly higher pullout strength than USS 5.0 mm (+30%, P = 0.014). The other screws did not differ significantly in pullout strength. Pullout strength correlated significantly with BMD (P = 0.0015) and vertebral body width/screw length (P < 0.001). The newly developed screws for spine surgery (USS II) show higher pullout strength when compared to established systems. Screw design had no significant influence on pullout force in vertebral body screws, but outer diameter of the screw, screw length and BMD are good predictors of pullout resistance.

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Influence of Screw Positioning in a New Anterior Spine Fixator on Implant Loosening in Osteoporotic Vertebrae

Cited by 39 publications

References 64 publications

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

Biomechanical and histological evaluation of an expandable pedicle screw in osteoporotic spine in sheep

Pullout strength of anterior spinal instrumentation: a product comparison of seven screws in calf vertebral bodies

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