Enrique Guerado

Surgical treatment of spondylodiscitis. An update

ConceptSpondylodiscitis refers to an infection affecting the intervertebral disk, the vertebral body or the posterior arch of the vertebra being aetiologically, pyogenic, granulomatous (tuberculosis, brucellosis, or fungal infection) or parasitic.DiagnosisSpondylodiscitis diagnosis is based on clinical symptoms, a combination of erythrocyte sedimentation rate with C-reactive protein (CRP) tests and, less useful, leukocytosis. Blood culture is also a very cost-effective method of identifying organisms. Plain radiographs are useful, however changes may take several months to appear. Radionuclide tests are currently less used; nevertheless, fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) shows encouraging results particularly when magnetic resonance images (MRI) are unconvincing in the distinction between degenerative changes and infection. MRI with gadolinium enhancement is the choice for image diagnosis.ManagementMedical management is usually the basis for treatment, alone or in combination with surgery. Surgical approach, either by endoscopy or open, is indicated for biopsy when clinical evolution is unsatisfactory and no micro-organism has been isolated, and also whenever a root, spinal cord or dural compression is seen on MRI; spinal instability or severe deformity are also clear indications for surgical treatment. Less invasive surgery either CT-scan guided or, particularly, by endoscopy has good results. However open surgery is still the standard. The anterior approach allows for anterior disc and bone debridement. The posterior approach is indicated when posterior elements are involved or in the presence of an epidural abscess. Although good results have been claimed, the use of instrumentation in the presence of an infected focus is controversial, as the use of cages or BMPs are.

Management of calcaneal fractures: what have we learnt over the years?

Calcaneal fractures result, in many cases, in, subtalar joint stiffness and severe disability. Diagnosis is usually made by X-ray, but more accurately by a computed tomography (CT) scan. In the last years, much has been known regarding its physiopathology and osteosynthesis. Although new developments in osteosynthesis materials have been made, calcaneus fractures still remains in dispute of those advocating non-operative treatment and those defending open reduction and internal fixation. Less invasive surgery, arthroscopy and three-dimensional (3D) fluoroscopy are very important for reduction accuracy and soft-tissue damage avoidance. In this article, the physiopathology, diagnosis, classification and treatment of calcaneus fractures are updated. Nevertheless, systematic reviews have shown no evidence about what treatment is better.

Zebrafish fins as a model system for skeletal human studies.

Recent studies on the morphogenesis of the fins of Danio rerio (zebrafish) during development and regeneration suggest that a number of inductive signals involved in the process are similar to some of those that affect bone and cartilage differentiation in mammals and humans. Akimenko et al. (2002) has shown that bone morphogenetic protein-2b (BMP2b) is involved in the induction of dermal bone differentiation during fin regeneration. Many other groups have also shown that molecules from the transforming growth factor-beta superfamily (TGFβ), including BMP2, are effective in promoting chondrogenesis and osteogenesis in vivo in higher vertebrates, including humans. In the present study, we review the state of the art of this topic by a comparative analysis of skeletal tissue development, regeneration and renewal processes in tetrapods, and fin regeneration in fishes. A general conclusion of this study states that lepidotrichia is a special skeletal tissue different to cartilage, bone, enamel, or dentine in fishes, according to its extracellular matrix (ECM) composition. However, the empirical analysis of inducing signals of skeletal tissues in fishes and tetrapods suggests that lepidotrichia is different to any responding features with main skeletal tissues. A number of new inductive molecules are arising from fin development and regeneration studies that might establish an empirical basis for further molecular approaches to mammal skeletal tissues differentiation. Despite the tissue dissimilarity, this empirical evidence might finally lead to clinical applications to skeletal disorders in humans.

What bone graft substitutes should we use in post-traumatic spinal fusion?

Surgical treatment of spinal fractures consists of postural reduction and segmental arthrodesis, together with an eventual performance of spinal canal decompression. Spinal arthrodesis consists of the combination of a hardware system for mechanical stabilisation together with a biological substance for enhancement of bone formation. To date, autologous graft is the only biological substance demonstrated to possess osteogenic properties. Cancellous bone graft has greater cellular activity than cortical graft, whereas cortical graft is stronger. Consequently, according to biological and biomechanical properties of autograft, spinal posterior arthrodesis is better enhanced by cancellous autograft, whereas anterior interbody tricortical bone is more suitable for anterior fusion. Allograft does not cause harvesting complications as autograft does, and also its amount is theoretically unlimited; nevertheless the rate of bone fusion facilitated by allograft is far from that enhanced by autograft given that allograft has no osteoprogenitor cells. There is little evidence on the efficacy of demineralised bone matrix for spinal fusion. Bone morphogenetic proteins (BMPs) are in use in spinal surgery, but their exact role with respect to type, dose, and carrier, together with their cost-effectiveness, need further clinical delineation. Calcium phosphate compounds appear to be good as carriers; however, they have no osteoinductive or osteogenic properties. Current clinical literature seem to indicate their usefulness for bony fusion in spinal surgery, when combined with bone marrow aspirate or used as an extender for autologous bone graft. Age, length of fusion, location, and concurrent diseases should be definitive for fusion outcome; papers on spinal arthrodesis should neatly stratify these variables. Unfortunately, since that is not the rule, conclusions drawn from current literature are very unreliable. Autograft remains the gold standard, and cancellous bone is advisable in posterolateral approaches, whereas tricortical iliac crest autograft appears appropriate for interbody support. In longer segments, its expansion with BMPs looks safe at least. Basic knowledge has been achieved from animal experiments, and clinical application of the findings to humans should be done very cautiously; in any case, both anterior and posterior arthrodesis must be protected with instrumentation used according to appropriate biomechanical principles. A combination of failure of the correct graft together with proper instrumentation will result in poorer outcome, even if the right graft is used.

Autologous human-derived bone marrow cells exposed to a novel TGF-β1 fusion protein for the treatment of critically sized tibial defect

We report the first clinical case of transplantation of autologous bone marrow-derived cells in vitro exposed to a novel recombinant human transforming growth factor (rhTGF)-beta1 fusion protein bearing a collagen-binding domain (rhTGF-beta(1)-F2), dexamethasone (DEX) and beta-glycerophosphate (beta-GP). When such culture-expanded cells were loaded into porous ceramic scaffolds and transplanted into the bone defect of a 69-year-old man, they differentiated into bone tissue. Marrow cells were obtained from the iliac crest and cultured in collagen gels impregnated with rhTGF-beta1-F2. Cells were selected under serum-restricted conditions in rhTGF-beta(1)-F2-containing medium for 10 days, expanded in 20% serum for 22 days and osteoinduced for 3 additional days in DEX/beta-GP-supplemented medium. We found that the cell number harvested from rhTGF-beta(1)-F2-treated cultures was significantly higher (2.3- to 3-fold) than that from untreated cultures. rhTGF-beta(1)-F2 treatment also significantly increased alkaline phosphatase activity (2.2- to 5-fold) and osteocalcin synthesis, while calcium was only detected in rhTGF-beta(1)-F2-treated cells. Eight weeks after transplantation, most of the scaffold pores were filled with bone and marrow tissue. When we tested the same human cells treated in vitro in a rat model using diffusion chambers, there was subsequent development of cartilage and bone following the subcutaneous transplantation of rhTGF-beta(1)-F2-treated cells. This supports the suggestion that such cells were marrow-derived cells, with chondrogenic and osteogenic potential, whereas the untreated cells were not under the same conditions. The ability for differentiation into cartilage and bone tissues, combined with an extensive proliferation capacity, makes such a marrow-derived stem cell population valuable to induce bone regeneration at skeletal defect sites.

Spondylodiscitis in patients under haemodyalisis

PurposeThe purpose of this study was to reach conclusions about the diagnosis and treatment of a series of patients with spondylodiscitis under haemodialysis treatment.MethodsWe collected and studied 23 patients included in a prospective database from two neighbouring hospitals. Descriptive statistical analysis was performed.ResultsThe diagnosis was frequently made very late and early negative cultures were not uncommon; magnetic resonance images allowed for an early diagnosis with accurate anatomical information. Empirical antibiotic treatment with prompt surgery produced good results in patients under risk of, or having neurological problems. Surgical approaches did not differ from pyogenic or tuberculous spondylodiscitis. Age in our series was not a predictive issue.ConclusionsWhenever a patient under haemodialysis has symptoms of spinal disease, particularly back pain with fever, they should undergo an MRI. If diagnosis of spondylodiscitis is made prompt empirical antibiotherapy should be instituted. Blood cultures should be performed and tissue samples taken for cultures; however, culture outcome must not delay therapy. Early surgical decompression leads to good results.

Characterization of Adult Stem/Progenitor Cell Populations From Bone Marrow in a Three-Dimensional Collagen Gel Culture System

Stem cell transplantation therapy using mesenchymal stem cells (MSCs) is considered a useful strategy. Although MSCs are commonly isolated by exploiting their plastic adherence, several studies have suggested that there are other populations of stem and/or osteoprogenitor cells that are removed from primary culture during media replacement. Therefore, we developed a three-dimensional (3D) culture system in which adherent and nonadherent stem cells are selected and expanded. Here, we described the characterization of 3D culture-derived cell populations in vitro and the capacity of these cells to differentiate into bone and/or cartilage tissue when placed inside of demineralized bone matrix (DBM) cylinders, implanted subcutaneously into the backs of rat for 2, 4, and 8 weeks. Our results demonstrates that 3D culture cells were a heterogeneous population of uncommitted cells that express pluripotent-, hematopoietic-, mesenchymal-, and endothelial-specific markers in vitro and can undergo osteogenic differentiation in vivo.

The physiopathology of avascular necrosis of the femoral head: an update

The physiopathology of the femoral head bone necrosis is similar for children and for adults. The disease is characterized by apoptosis of bone cells - bone marrow and bone forming cells-resulting in head collapse with a subsequent lesion of the overlying cartilage, and therefore flattening of the rounded surface shape of the head articulating with the acetabulum, provoking, eventually, secondary osteoarthritis. When the disease becomes clinically evident already destructive phenomena have occurred and collapse will eventually ensue. In children, because epiphyseal cartilage has growth capabilities, lost epiphyseal height can be recovered, however in adults collapse is irreversible. In this paper the physiopathology of this disease is examined as well as its implication for treatment. Prevention by genetic studies is discussed.

Treatment of Periprosthetic Infections: An Economic Analysis

This review summarizes the existing economic literature, assesses the value of current data, and presents procedures that are the less costly and more effective options for the treatment of periprosthetic infections of knee and hip. Optimizing antibiotic use in the prevention and treatment of periprosthetic infection, combined with systemic and behavioral changes in the operating room, the detection and treatment of high-risk patient groups, as well as the rational management of the existing infection by using the different procedures according to each particular case, could allow for improved outcomes and lead to the highest quality of life for patients and the lowest economic impact. Nevertheless, the costeffectiveness of different interventions to treat periprosthetic infections remains unclear.

Surgical technique: Intraacetabular osteosynthesis with arthroplasty for acetabular fracture in the octogenarian

Acetabular fractures in elderly patients need prompt and proper diagnosis and treatment, as delay for management and early failures with subsequent salvage surgery can be accompanied by significant morbidity. Treatment options available include closed management, open reduction with internal fixation (ORIF), and acute or staged total hip arthroplasty (THA) whether alone or combined with osteosynthesis by a wire cerclage. In the case of octogenarian patients, since there is significant destruction of the articular cartilage, primary THA may provide the best solution. Removal of the femoral head allows for excellent exposure of the acetabulum, making it possible to stabilize most fractures without the need for extensile approaches. In older individuals with severe osteoporosis as octogenarians, a typical fracture pattern results in intrapelvic dislocation of the femoral head with a blowout fracture of the anterior column and medial wall. In this paper we present a simple, minimal, and cost-effective osteosynthesis technique performed in the course of a straightforward THA for the treatment of acetabular fractures in octogenarian patients.