GEORG-SCHMORL-PRIZE OF THE GERMAN SPINE SOCIETY (DWG) 2016: Comparison of in vitro osteogenic potential of iliac crest and degenerative facet joint bone autografts for intervertebral fusion in lumbar spinal stenosis

History of Bone Grafts in Spine Surgery

Bone grafting replaces damaged or missing bone with new bone and is used for surgical arthrodesis. Patients benefit from a huge variety of bone graft techniques and options for spinal fusions. This article reviews the rich history of bone grafts in surgery with particular emphasis on spinal fusion. During the early years of bone grafting in spine surgery, bone grafts were used on tuberculosis patients, and the structural support of the graft was most the important consideration. Between 1960 and 2000, many advances were made, specifically in the use of bone graft substitutes. The field of bone grafts in spine surgery has evolved rapidly since first described.

Current concepts and recent advances in understanding and managing lumbar spine stenosis

Lumbar spinal stenosis is a degenerative process that is extremely frequent in today's aging population. It can result in impingement on the nerves of the cauda equina or on the thecal sac itself, and lead to debilitating symptoms such as severe leg pain, or restriction in the perimeter of ambulation, both resulting in dependency in daily activities. The impact of the disease is global and includes financial repercussions because of its involvement in the active work force group. Risk factors for the disease include some comorbidities such as obesity or smoking, daily habits such as an active lifestyle, but also genetic factors that are not completely elucidated yet. The diagnosis of lumbar stenosis can be difficult, and involves a combination of radiological and clinical findings. Treatment ranges from conservative measures with physical therapy and core strengthening, to steroid injections in the facet joints or epidural space, to a more radical solution with surgical decompression. The evidence available in the literature regarding the causes, diagnosis and treatment of lumbar spine stenosis can be confusing, as no level I recommendations can be provided yet based on current data. The aim of this manuscript is to provide a comprehensive and updated summary to the reader addressing the multiple aspects of this disease.

Alterations of Subchondral Bone Progenitor Cells in Human Knee and Hip Osteoarthritis Lead to a Bone Sclerosis Phenotype

Subchondral bone tissue plays a key role in the initiation and progression of human and experimental osteoarthritis and has received considerable interest as a treatment target. Elevated bone turnover and remodeling leads to subchondral bone sclerosis that is characterized by an increase in bone material that is less mineralized. The aim of this study was to investigate whether perturbations in subchondral bone-resident progenitor cells might play a role in aberrant bone formation in osteoarthritis. Colony formation assays indicated similar clonogenicity of progenitor cells from non-sclerotic and sclerotic subchondral trabecular bone tissues of osteoarthritic knee and hip joints compared with controls from iliac crest bone. However, the osteogenic potential at the clonal level was approximately two-fold higher in osteoarthritis than controls. An osteogenic differentiation assay indicated an efficient induction of alkaline phosphatase activity but blunted in vitro matrix mineralization irrespective of the presence of sclerosis. Micro-computed tomography and histology demonstrated the formation of de novo calcified tissues by osteoblast-like cells in an ectopic implantation model. The expression of bone sialoprotein, a marker for osteoblast maturation and mineralization, was significantly less in sclerotic progenitor cells. Perturbation of resident progenitor cell function is associated with subchondral bone sclerosis and may be a treatment target for osteoarthritis.