Stefan Schaeren

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Mesenchymal stem/stromal cells (MSC) are typically used to generate bone tissue by a process resembling intramembranous ossification, i.e., by direct osteoblastic differentiation. However, most bones develop by endochondral ossification, i.e., via remodeling of hypertrophic cartilaginous templates. To date, endochondral bone formation has not been(More)
Bisphosphonates are well known potent inhibitors of osteoclast activity and are widely used to treat metabolic bone diseases. Recent evidence from in vitro and in vivo studies indicates that bisphosphonates may additionally promote osteoblastic bone formation. In this study, we evaluated the effects of three FDA-approved and clinically utilized(More)
STUDY DESIGN Prospective clinical study. OBJECTIVE To test whether elastic stabilization with the Dynesys system (Zimmer Spine, Minneapolis, MN) provides enough stability to prevent further progression of spondylolisthesis as well as instability after decompression for spinal stenosis with degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA In(More)
STUDY DESIGN Prospective clinical study. OBJECTIVE To test whether posterior dynamic stabilization in situ with Dynesys (Zimmer Spine, Minneapolis, MN) can maintain enough stability to prevent progression of spondylolisthesis in long-term follow-up. SUMMARY OF BACKGROUND DATA In spinal stenosis with degenerative spondylolisthesis, decompression and(More)
Vertebral osteomyelitis caused by non-tuberculous mycobacteria is a rare disease, with only 31 cases and one nosocomial outbreak reported in the literature (MedLine review between 1965 and December 2003). The clinical features are often indistinguishable from those of pyogenic osteomyelitis. Early diagnosis of such infections is a major challenge because of(More)
Implant removal because of pain after posterior fusion in the thoracic and lumbar spine is a widely performed operation. We conducted a retrospective study to examine whether patients benefit from implant removal. 57 patients (29 males, 28 females, mean age 46.5 years) who have undergone removal of pedicle screws because of pain and discomfort were(More)
OBJECTIVE To document the specificity and the mechanism of induction of a novel class II major histocompatibility complex (MHC) antigen by mitogenic growth factors in human mesenchymal stem cells (MSCs) expanded in vitro for translational applications. METHODS Expression of class II MHC molecules was measured in human MSCs and differentiated cells(More)
Fractures of the atlas account for 1–2 % of all vertebral fractures. We divide atlas fractures into 5 groups: isolated fractures of the anterior arch of the atlas, isolated fractures of the posterior arch, combined fractures of the anterior and posterior arch (so-called Jefferson fractures), isolated fractures of the lateral mass and fractures of the(More)
Osteoporosis is not only responsible for an increased number of metaphyseal and spinal fractures but it also complicates their treatment. To prevent the initial loosening, we developed a new implant with an enlarged implant/bone interface based on the concept of perforated, hollow cylinders. We evaluated whether osseointegration of a hollow cylinder based(More)
PURPOSE To report a comparative study on postoperative management following percutaneous repair of acute Achilles tendon ruptures. METHODS One hundred and three patients with percutaneous repair after acute Achilles tendon rupture were prospectively entered in our departmental database. Before July 1999, 15 patients were treated postoperatively with(More)