Bioglass/PLGA associated to photobiomodulation: effects on the healing process in an experimental model of calvarial bone defect

Bioactive glasses (BG) are known for their ability to bond to bone tissue. However, in critical situations, even the osteogenic properties of BG may be not enough to induce bone consolidation. Thus, the enrichment of BG with polymers such as Poly (D, L-lactic-co-glycolic) acid (PLGA) and associated to photobiomodulation (PBM) may be a promising strategy to promote bone tissue healing. The aim of the present study was to investigate the in vivo performance of PLGA supplemented BG, associated to PBM therapy, using an experimental model of cranial bone defect in rats. Rats were distributed in 4 different groups (Bioglass, Bioglass/PBM, Bioglas/PLGA and BG/PLGA/PBM). After the surgical procedure to induce cranial bone defects, the pre-set samples were implanted and PBM treatment (low-level laser therapy) started (808 nm, 100 mW, 30 J/cm²). After 2 and 6 weeks, animals were euthanized, and the samples were retrieved for the histopathological, histomorphometric, picrosirius red staining and immunohistochemistry analysis. At 2 weeks post-surgery, it was observed granulation tissue and areas of newly formed bone in all experimental groups. At 6 weeks post-surgery, BG/PLGA (with or without PBM) more mature tissue around the biomaterial particles. Furthermore, there was a higher deposition of collagen for BG/PLGA in comparison with BG/PLGA/PBM, at second time-point. Histomorphometric analysis demonstrated higher values of BM.V/TV for BG compared to BG/PLGA (2 weeks post-surgery) and N.Ob/T.Ar for BG/PLGA compared to BG and BG/PBM (6 weeks post-surgery). This current study concluded that the use of BG/PLGA composites, associated or not to PBM, is a promising strategy for bone tissue engineering.

EVALUATION OF STRUCTURAL CHANGES IN THE AREA OF EXPERIMENTAL MANDIBULAR DEFECT WHEN APPLYING OSTEOPLASTIC MATERIALS BASED ON VARIOUS COMPONENT PERCENTAGE OF HYDROXYAPATITE AND POLYLACTIDE

The main aim is to find out the mechanisms of reparative regeneration of bone tissue in artificially created transverse mandibular defects in rats when applying osteoplastic materials based on hydroxyapatite and polylactide with different component percentage. Experimental studies were carried out on 114 mature laboratory white male 180-220 g rats that were divided into groups: control group - animals whose bone defect was filled only with a blood clot; 1st experimental group - the entire defect volume was densely filled with a block with the ratio of component parts, hydroxyapatite 80% + polylactide 20%; 2nd experimental group was similar, but with the ratio of 50% + 50%. Morphological and morphometric research methods were carried out after the removed jaws had been decalcized in a 10% nitric acid solution. An x-ray study was performed using an Intra digital radiograph (Planmeca, Finland). Statistical analysis of the results was carried out according to the standard method of descriptive statistics using the software package "StatSoftStatistica 10". The use of osteoplastic material with a longer period of its biodegradation contributes to filling the defect with bone tissue, but slows down the processes of the final formation of a mature secondary bone scar, yet allows even with hypercorrection to restore the anatomical form of the lost area. Therefore, the use of this material is recommended for a defect in the alveolar ridge, mainly in extraction sockets, when one needs to avoid atrophy and to create conditions for prosthetic treatment. Osteoimplant with a faster biodegradation period allows structuring collagen fibers in the regenerate in the early stages of healing, which optimizes the formation of an organic bone matrix and promotes its faster mineralization. Therefore, such bone substitutes can be better used for insignificant defects or when the restoration of the anatomical form is not essential, mainly for defects of the body and mandibular branches.

Supplementation with 45S5 Bioactive Glass Reduces In Vivo Resorption of the β-Tricalcium-Phosphate-Based Bone Substitute Material Vitoss

Compared to other materials such as 45S5 bioactive glass (BG), β-tricalcium phosphate (β-TCP)-based bone substitutes such as Vitoss show limited material-driven stimulation of osteogenesis and/or angiogenesis. The unfavorable degradation kinetics of β-TCP-based bone substitutes may result in an imbalance between resorption and osseous regeneration. Composite materials like Vitoss BA (Vitoss supplemented with 20 wt % 45S5-BG particles) might help to overcome these limitations. However, the influence of BG particles in Vitoss BA compared to unsupplemented Vitoss on osteogenesis, resorption behavior, and angiogenesis is not yet described. In this study, Vitoss and Vitoss BA scaffolds were seeded with human mesenchymal stromal cells before subcutaneous implantation in immunodeficient mice for 10 weeks. Scaffold resorption was monitored by micro-computed tomography, while osteoid formation and vascularization were assessed by histomorphometry and gene expression analysis. Whilst slightly more osteoid and improved angiogenesis were found in Vitoss BA, maturation of the osteoid was more advanced in Vitoss scaffolds. The volume of Vitoss implants decreased significantly, combined with a significantly increased presence of resorbing cells, whilst the volume remained stable in Vitoss BA scaffolds. Future studies should evaluate the interaction of 45S5-BG with resorbing cells and bone precursor cells in greater detail to improve the understanding and application of β-TCP/45S5-BG composite bone substitute materials.

Clinical and radiographic evaluation of bioactive glass in posterior cervical and lumbar spinal fusion

INTRODUCTION

Spinal surgery of degenerative painful segments is a valuable treatment option in the management of chronic cervical and low back pain. The surgery consists in stabilizing and fusing painful vertebral segment(s). The objective of the study was to report our experience with 45S5 bioactive glass (BAG) to obtain inter-vertebral fusion in the context of posterior spine surgery.

MATERIAL AND METHOD

In this retrospective study, 30 patients with a wide range of degenerative and traumatic conditions of the cervical or lumbar spine underwent spinal fusion utilizing a synthetic bone graft substitute of BAG (GlassBone™, Noraker, Lyon-Villeurbanne, France). The pain was evaluated by VAS score, and graft consolidation was assessed on according radiographic images at 1-year post-op.

RESULTS

All patients underwent posterior spinal fusion either in the cervical or the thoraco-lumbar spine. Multi-level fusions represented the majority of the cohort (43% of patients with more than seven levels treated). Radiographic imaging demonstrated excellent fusion rates (93%) at final follow-up, equivalent to the outcomes reported in the literature for autogenous bone, with excellent bone bridging and no spinal implant loosening. Only two cases of non-union were encountered. Additionally, 90% of the patients demonstrated recovery at 1 year after surgery with a pain reduction of 60%.

CONCLUSION

The results of this retrospective study suggest that the 45S5 BAG may be an interesting alternative option to autologous graft, in terms of safety and bone fusion efficiency.

LEVEL OF EVIDENCE

IV Retrospective study.

Treatment of radius or ulna fractures in the elderly: A systematic review covering effectiveness, safety, economic aspects and current practice

Background

The objective of the present study was to evaluate effectiveness, complications and cost-effectiveness of any surgical or non-surgical treatment for radius or ulna fractures in elderly patients. Secondary objectives were to analyze present treatment traditions of distal radius fractures (DRF) in Sweden and to calculate resource usage for its treatment.

Methods and findings

The assessment contains a systematic review of clinical and health economic studies comparing treatment options for radius or ulna fractures. The results regarding the effectiveness of the treatments are summarized in meta-analyses. In addition, the assessment contains a cost analysis for different treatment options commonly used for DRF care, and an analysis of registry data on the incidence and treatment of DRF. In total 31 randomized controlled trials were included in meta-analyses. When comparing functional outcome for plate fixation versus non-surgical treatment for DRF, there were no clinically important differences at one-year follow-up (mean difference [MD], -3.29, 95% CI, -7.03; 0.44). Similar results were found when comparing plating and percutaneous methods with respect to functional outcome (standardized mean difference [SMD], -0.07, 95% CI, -0.21; 0.07) and grip strength (MD, -3.47, 95% CI, -11.21; 4.28). There were no differences for minor complications, (risk difference [RD], -0.01, 95% CI, -0.07; 0.05) whereas major complications were less common for the percutaneous group, (RD, 0.02, 95% CI, 0.02; 0.03). Given the low number of studies, the evidence above was rated as moderate certainty. The cost for plate fixation versus plaster cast was estimated to 1698 compared to 137 US dollars. For DRF, plate fixation increased in Sweden between 2005 and 2013, and was the most common surgical method in 2013.

Conclusions

Surgical treatment of moderately displaced distal radius fractures in elderly patients offers no clear benefit compared to non-surgical treatment. Plating procedures have become more common during the second millennium and involve higher costs and higher risk of major complications than percutaneous options.

P2000 - A high-nitrogen austenitic steel for application in bone surgery

Optimal treatment of bone fractures with minimal complications requires implant alloys that combine high strength with high ductility. Today, TiAl6V4 titanium and 316L steel are the most applied alloys in bone surgery, whereas both share advantages and disadvantages. The nickel-free, high-nitrogen austenitic steel X13CrMnMoN18-14-3 (1.4452, brand name: P2000) exhibits high strength in combination with superior ductility. In order to compare suitable alloys for bone implants, we investigated titanium, 316L steel, CoCrMo and P2000 for their biocompatibility and hemocompatibility (according to DIN ISO 10993-5 and 10993-4), cell metabolism, mineralization of osteoblasts, electrochemical and mechanical properties. P2000 exhibited good biocompatibility of fibroblasts and osteoblasts without impairment in vitality or changing of cell morphology. Furthermore, investigation of the osteoblasts function by ALP activity and protein levels of the key transcription factor RUNX2 revealed 2x increased ALP activity and more than 4x increased RUNX2 protein levels for P2000 compared to titanium or 316 steel, respectively. Additionally, analyses of osteoblast biomineralization by Alizarin Red S staining exhibited more than 6x increased significant mineralization of osteoblasts grown on P2000 as compared to titanium. Further, P2000 showed no hemolytic effect and no significant influence on hemocompatibility. Nanoindentation hardness tests of Titanium and 316L specimens exposed an indentation hardness (HIT) of about 4 GPa, whereas CoCrMo and P2000 revealed HIT of 7.5 and 5.6 GPa, respectively. Moreover, an improved corrosion resistance of P2000 compared to 316L steel was observed. In summary, we could demonstrate that the nickel-free high-nitrogen steel P2000 appears to be a promising alternative candidate for applications in bone surgery. As to nearly all aspects like biocompatibility and hemocompatibility, cell metabolism, mineralization of osteoblasts and mechanical properties, P2000 was similar to or revealed advantages against titanium, 316L or CoCrMo.

Alveolar Ridge Preservation Using Tridimensional Collagen Matrix and Deproteinized Bovine Bone Mineral in the Esthetic Area: A CBCT and Histologic Human Pilot Study

Alveolar ridge preservation is of great importance for successful implant therapy. This study investigated the effects of a xenogeneic tridimensional collagen matrix (CM) in conjunction with deproteinized bovine bone mineral blended with 10% collagen (DBBM-C) on the healing of 12 intact extraction sockets in the esthetic area. Cone beam computed tomograpy examinations revealed nearly stable alveolar ridge dimensions (> 90% of the ridge horizontal dimension was preserved). New bone formation of approximately 45% and adequate resorption of the grafted material were histologically observed. Thus, application of CM together with DBBM-C using minimally invasive flapless approach can preserve the original ridge volume and support bone formation, contributing to adequate bone volume for implant insertion.

Three-dimensional (3D) printed scaffold and material selection for bone repair

Critical-sized bone defect repair remains a substantial challenge in clinical settings and requires bone grafts or bone substitute materials. However, existing biomaterials often do not meet the clinical requirements of structural support, osteoinductive property, and controllable biodegradability. To treat large-scale bone defects, the development of three-dimensional (3D) porous scaffolds has received considerable focus within bone engineering. A variety of biomaterials and manufacturing methods, including 3D printing, have emerged to fabricate patient-specific bioactive scaffolds that possess controlled micro-architectures for bridging bone defects in complex configurations. During the last decade, with the development of the 3D printing industry, a large number of tissue-engineered scaffolds have been created for preclinical and clinical applications using novel materials and innovative technologies. Thus, this review provides a brief overview of current progress in existing biomaterials and tissue engineering scaffolds prepared by 3D printing technologies, with an emphasis on the material selection, scaffold design optimization, and their preclinical and clinical applications in the repair of critical-sized bone defects. Furthermore, it will elaborate on the current limitations and potential future prospects of 3D printing technology. STATEMENT OF SIGNIFICANCE: 3D printing has emerged as a critical fabrication process for bone engineering due to its ability to control bulk geometry and internal structure of tissue scaffolds. The advancement of bioprinting methods and compatible ink materials for bone engineering have been a major focus to develop optimal 3D scaffolds for bone defect repair. Achieving a successful balance of cellular function, cellular viability, and mechanical integrity under load-bearing conditions is critical. Hybridization of natural and synthetic polymer-based materials is a promising approach to create novel tissue engineered scaffolds that combines the advantages of both materials and meets various requirements, including biological activity, mechanical strength, easy fabrication and controllable degradation. 3D printing is linked to the future of bone grafts to create on-demand patient-specific scaffolds.

Biological Properties of Calcium Phosphate Bioactive Glass Composite Bone Substitutes: Current Experimental Evidence

Standard treatment for bone defects is the biological reconstruction using autologous bone—a therapeutical approach that suffers from limitations such as the restricted amount of bone available for harvesting and the necessity for an additional intervention that is potentially followed by donor-site complications. Therefore, synthetic bone substitutes have been developed in order to reduce or even replace the usage of autologous bone as grafting material. This structured review focuses on the question whether calcium phosphates (CaPs) and bioactive glasses (BGs), both established bone substitute materials, show improved properties when combined in CaP/BG composites. It therefore summarizes the most recent experimental data in order to provide a better understanding of the biological properties in general and the osteogenic properties in particular of CaP/BG composite bone substitute materials. As a result, BGs seem to be beneficial for the osteogenic differentiation of precursor cell populations in-vitro when added to CaPs. Furthermore, the presence of BG supports integration of CaP/BG composites into bone in-vivo and enhances bone formation under certain circumstances.

Regenerative Periodontal Treatment with the Single Flap Approach in Smokers and Nonsmokers

The present study was performed to evaluate the impact of smoking status on 6-month clinical outcomes of a regenerative procedure based on enamel matrix derivative and deproteinized bovine bone mineral in the treatment of intraosseous defects accessed with buccal single flap approach. A total of 22 defects were selected in smoking (n = 11) and nonsmoking (n = 11) patients. Regenerative treatment resulted in similar clinical attachment level (CAL) gain in both smokers and nonsmokers. A trend toward lower 6-month CAL gain and probing depth reduction was observed in patients smoking 11 to 20 cigarettes per day compared to those smoking 1 to 10 cigarettes per day.

Dimensional Evaluation of Different Ridge Preservation Techniques with a Bovine Xenograft: A Randomized Controlled Clinical Trial

The objectives of this study were to determine the quantitative changes after different ridge preservation techniques (primary aim) and to assess the possibility of placing a dental implant, the bone quality, and the need for bone augmentation (secondary aim). A total of 35 patients who required extraction of at least one tooth (incisor, canine, or premolar) provided 35 single-gap extraction sites. After minimally invasive tooth removal, the sockets were randomly scheduled for one of four treatment modalities: placement of a deproteinized bovine bone mineral (DBBM; Endobon, Biomet 3i) covered with a soft tissue punch from the palate (T1); placement of DBBM alone (T2); placement of DBBM covered with a resorbable collagen membrane (OsseoGuard, Biomet 3i) (T3); or no additional treatment (T4). Silicone impressions were taken before and 6 months after extraction for quantitative-volumetric evaluation (primary outcome). The possibility of placing an implant, bone quality, and need for further bone augmentation were also noted (secondary outcomes). During the study period, no adverse events were observed. No statistically significant difference was found between the four treatments regarding the primary and secondary outcome parameters (P > .05). However, T4 showed double the buccal contour change, with the highest variance compared to the other three groups (T1 -0.874 ± 0.713; T2 -0.968 ± 0.344; T3 -1.26 ± 0.942; T4 -2.15 ± 1.349). Although no statistically significant difference was found between the four treatment modalities, placement of DBBM resulted in only half the contour change (< 1 mm) compared to control sites (> 2 mm). Ridge preservation with a DBBM with or without soft tissue punch should be considered in esthetically demanding cases and delayed or late implant placement.

Electrospun PLGA and β-TCP (Rebossis-85) in a Lapine Posterolateral Fusion Model

BACKGROUND

Calcium phosphate materials have been employed clinically as bone void fillers for several decades. These materials are most often provided in the form of small, porous granules that can be packed to fill the wide variety of size and shape of bony defects encountered. ReBOSSIS-85 (RB-85) is a synthetic bioresorbable bone void filler for the repair of bone defects with handling characteristics of glass wool-like (or cotton ball-like). The objective of this study is to evaluate the in vivo performance of RB-85 (test material), compared to a commercially available bone void filler, Mastergraft Putty (predicate material), when combined with bone marrow aspirate and iliac crest autograft, in an established posterolateral spine fusion rabbit model.

METHODS

One hundred fifty skeletally mature rabbits had a single level posterolateral fusion performed. Rabbits were implanted with iliac crest bone graft (ICBG), Mastergraft Putty™ plus ICBG, or one of 4 masses of ReBOSSIS-85 (0.2, 0.3, 0.45, or 0.6 g) plus ICBG. Plain films were taken weekly until euthanasia. Following euthanasia at 4, 8, and 12 weeks, the lumbar spine were tested by manual palpation. Spinal columns in the 12 week group were also subjected to non-destructive flexibility testing. MicroCT and histology were performed on a subset of each implant group at each euthanasia period.

RESULTS

Radiographic scoring of the fusion sites indicated a normal healing response in all test groups. Bilateral radiographic fusion rates for all test groups were 0% at 4 weeks; ICBG 43%, Mastergraft Putty 50%, RB-85-0.2g 0%, RB-85-0.3g 13%, RB-85-0.45g 38%, and RB-85-0.6g 63% at 8 weeks; and ICBG 50%, Mastergraft Putty 50%, RB-85-0.2g 0%, RB-85-0.3g 25%, RB-85-0.45g 36%, and RB-85-0.6g 50% at 12 weeks.Spine fusion was assessed by manual palpation of the treated motion segments. At 12 weeks, ICBG, MGP, and RB-85-0.6g were fused mechanically in at least 50% of the rabbits. All groups demonstrated significantly less range of motion in both flexion/extension, lateral bending, and axial rotation compared to normal unfused controls.Histopathology analysis of the fusion masses, in all test groups, indicated an expected normal response of mild inflammation with macrophage and multinucleated giant cell response to the graft material at 4 weeks and resolving by 12 weeks. Regardless of test article, new bone formation and graft resorption increased from 4 to 12 weeks post-op.

CONCLUSIONS

This animal study has demonstrated the biocompatibility and normal healing features associated with the ReBOSSIS-85 bone graft (test material) when combined with autograft as an extender. ReBOSSIS-85 was more effective when a larger mass of test article was used in this study.

CLINICAL RELEVANCE

ReBOSSIS-85 can be used as an extender negating the need for large amounts of local or iliac crest bone in posterolateral fusions.

Arthroscopic treatment of osteochondral knee defects with resorbable biphasic synthetic scaffold: clinical and radiological results and long-term survival analysis

PURPOSE

The aim of our study is to evaluate the long-term results in patients treated with a fully arthroscopic TruFit system for osteochondral lesions of the femoral condyle, analyzing the clinical and radiological outcomes, survival rate, complications, and correlations.

METHODS

The study included all patients treated with the TruFit system with a full-thickness focal lesion of the knee cartilage (grade IV according to the ICRS classification), entirely arthroscopically with a minimum follow-up of five years. All patients were evaluated clinically prior to surgery (T₀) and at two consecutive follow-ups (T₁ 36.4 ± 17.03 months and T₂ 101.63 ± 19.02 months), using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Hospital for Special Surgery Score (HSS). At the final follow-up, the magnetic resonance imaging (MRI) was evaluated by two orthopaedists using the magnetic resonance observation of cartilage repair tissue (MOCART) score.

RESULTS

The sample was formed of 21 patients, of which 14 were males (67%) and 7 females (33%), with a mean age of 51.29 ± 10.70. Of the 21 patients, two underwent prosthetic knee replacement at 24 and 65 months, respectively. At T₀, the HSS and the KOOS score were, respectively, 60.71 ± 11.62 and 57.71 ± 6.11. For both clinical values, a significant improvement was noted between T₀ and T₁ (p < 0.05) and between T₀ and T₂ (p < 0.05). At the final follow-up, the MOCART value was found to be 45.78 ± 5.27.

CONCLUSIONS

The study results highlighted the safety and potential of the arthroscopic TruFit system procedure, which offered a good clinical outcome with stable results at long-term follow-up although we found no correlations between the MRI and clinical results.

A prospective histomorphometric and cephalometric comparison of bovine bone substitute and autogenous bone grafting in Le Fort I osteotomies

PURPOSE

The aim of the present study was the histomorphometric and cephalometric comparison of autogenous bone grafting of the anterior iliac crest and the application of bovine bone substitute concerning new bone formation and postoperative stability in patients undergoing orthognathic Le Fort I osteotomy.

PATIENTS AND METHODS

Twenty-five patients requiring orthognathic surgery with Le Fort I osteotomy were included in this study. Patients were randomly divided into three groups receiving either autogenous iliac crest BONE grafting (BONE; n = 8) or xenogenic bovine bone grafting (Bio-Oss^®) in INTER (n = 12) or in ONLAY (n = 5) position. Histomorphometric analysis was performed using trephine bone biopsies from the autogenous, respectively xenogenic bone grafting region. Postoperative stability was evaluated using teleradiographies of three different timepoints.

RESULTS

All groups showed comparable mineralized fractions in bone biopsies of 50.2% (±13.2%) INTER, 46.48% (±12.3%) ONLAY and 57.1% (±20.6%) BONE as well as comparable percentage of connective tissue. Patients in the INTER-group revealed the lowest relapse rate of 20.5% (INTER) compared to 30.3% (ONLAY) and 33.0% (BONE). All groups underwent comparable maxillary advancement and healing time.

CONCLUSIONS

Present results indicate that block shaped bovine bone substitute is a promising alternative to autogenous bone grafting to bridge the Le Fort I osteotomy gap in orthognathic surgery.

Clinical and CBCT Evaluation of Combined Periodontal Regenerative Therapies Using Enamel Matrix Derivative and Deproteinized Bovine Bone Mineral With or Without Collagen Membrane

Use of collagen membrane (CM) with deproteinized bovine bone mineral (DBBM) and enamel matrix derivative (EMD) in periodontal regenerative therapy was evaluated. A total of 40 intrabony defects in periodontitis patients were treated. Clinical parameters and filled bone volume (FBV) and rate (FBR) were assessed. Probing pocket depth (PPD) was reduced significantly at 12 months with CM treatment, while clinical attachment level (CAL), FBV, and FBR showed similar improvements. In stratified analyses, CM-treated thick-biotype patients showed significant improvement in PPD and CAL. Regenerative therapy with the use of EMD and DBBM showed similar improvements in periodontal tissue regeneration with or without CM. The combination with CM appeared to influence the healing of soft tissue and was effective in decreasing pocket depth.

Epigallocatechin Gallate-Modified Gelatins with Different Compositions Alter the Quality of Regenerated Bones

Bone quality is a significant indicator of the result of bone treatments. However, information regarding the quality of regenerated bones is limited. The study investigates the effect of different compositions of vacuum heated epigallocatechin gallate-modified gelatins sponge (vhEGCG-GS) on the quality of regenerated bones in critical size defects (9 mm) of rat calvariae. Five different compositions of vhEGCG-GSs containing the same amount of EGCG and different amounts of gelatin were tested. Following four weeks after implantation, the harvested regenerated bones were evaluated by using micro-computed tomography analysis, histological evaluation (hematoxylin-eosin and Villaneueva Goldner staining), picrosirius red-staining with polarized microscopic observation for collagen maturation, and Fourier transform infrared spectroscopy microscopy and imaging analysis for mineral-matrix ratio. The results indicated that increasing content of gelatin in the vhEGCG-GSs promoted bone and osteoid formation but yielded porous bones. Furthermore, tissue mineral density decreased and the maximum mineral-matrix ratio increased. In contrast, vhEGCG-GSs containing smaller amount of gelatin formed mature collagen matrix in the regenerated bones. These results suggest that the alteration of composition of vhEGCG-GSs affected the bone forming capability and quality of regenerated bone and provides valuable insight for the fabrication of new bone substitute materials.

Autologous cell-based therapy for treatment of large bone defects: from bench to bedside

OBJECTIVES

Reconstruction of long segmental bone defects is demanding for patients and surgeons, and associated with long-term treatment periods and substantial complication rates in addition to high costs. While defects up to 4-5 cm length might be filled up with autologous bone graft, heterologous bone from cadavers, or artificial bone graft substitutes, current options to reconstruct bone defects greater than 5 cm consist of either vascularized free bone transfers, the Masquelet technique or the Ilizarov distraction osteogenesis. Alternatively, autologous cell transplantation is an encouraging treatment option for large bone defects as it eliminates problems such as limited autologous bone availability, allogenic bone immunogenicity, and donor-site morbidity, and might be used for stabilizing loose alloplastic implants.

METHODS

The authors show different cell therapies without expansion in culture, with ex vivo expansion and cell therapy in local bone defects, bone healing and osteonecrosis. Different kinds of cells and scaffolds investigated in our group as well as in vivo transfer studies and BMC used in clinical phase I and IIa clinical trials of our group are shown.

RESULTS

Our research history demonstrated the great potential of various stem cell species to support bone defect healing. It was clearly shown that the combination of different cell types is superior to approaches using single cell types. We further demonstrate that it is feasible to translate preclinically developed protocols from in vitro to in vivo experiments and follow positive convincing results into a clinical setting to use autologous stem cells to support bone healing.

Sinus Floor Elevation Using the Lateral Approach and Window Repositioning and a Xenogeneic Bone Substitute as a Grafting Material: A Histologic, Histomorphometric, and Radiographic Analysis

PURPOSE

Sinus floor elevation using the lateral approach and bone window repositioning and a xenogeneic bone substitute (Cerabone) has been well documented clinically. The purpose of this histologic and histomorphometric study was to determine the fate of the window, its contributing role in the healing process, and the osseoconductivity and resorption potential of the high-temperature sintered bovine bone used, as well as to correlate the histomorphometric results with sinus depth and lateral wall thickness as determined on cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Thirty biopsy specimens were harvested from the lateral side of the maxilla of patients operated on for sinus floor elevation and implant placement at two postoperative periods: early, group 1 (mean: 5.73 ± 0.44 months); and late, group 2 (mean: 8.68 ± 1.76 months). Sinus depth and lateral wall thickness were determined on CBCT and correlated to graft maturation.

RESULTS

The repositioned bone window was microscopically detectable in both study groups and looked well integrated. Bone was found growing out of the repositioned window toward the center of the graft, most often forming a trabecular network independently from the bone matrix, which is in favor of osteogenic potential of the window. Also, newly built bone was found directly attached to the surfaces of the window, indicating bone growth via osseoconduction. Repositioned window sides showed signs of low-grade inflammation. Active osteoclasts were only found to be associated with the newly built bone matrix, hinting at an active bone remodeling process. No signs of biodegradation or remodeling of the window were detected using the tartrate-resistant acid phosphatase (TRAP) technique. The histomorphometric analysis of the tissue distribution showed similar values of newly formed bone in group 1 (22.77% ± 5.89%) and in group 2 (26.15% ± 11.18%) and connective tissue values in both study groups (42.29% ± 8.98% for group 1 vs 46.03% ± 5.84% for group 2). No significant differences were found between group 1 (34.94% ± 7.10%) and group 2 (27.82% ± 11.97%) for xenogeneic bone substitute values. Statistically significant differences were only found between connective tissue values and newly built bone values (P < .01 and P < .001, respectively). Furthermore, a significant difference was found between connective tissue values and that of bone substitute up to 12 months (P < .01). No significant correlation was found between sinus depth and lateral window thickness and histomorphometric results.

CONCLUSION

The re positioned window technique appears to be a good osteoconductive barrier for bone formation. Its osteogenic potential needs to be confirmed immunochemically. High-temperature sintered bovine bone proved to be an effective slowly resorbing osseoconductive material.

Releasing Incisions Using Upward-Motion Scissors Technique for Flap Mobilization for Guided Bone Regeneration or Periodontal Surgery: Technical Introduction and a Case Report

Flap management is one of the key elements for success in periodontal surgeries and bone regeneration for dental implants. The aim of this article is to introduce a releasing incision method for effective flap advancement to obtain tension-free primary closure. The 'upward-motion scissors technique' (UMST) involves the use of surgical scissors handled with an upward motion to create multiple shallow incisions. The use of UMST is demonstrated in an anatomically challenging case requiring bone augmentation. This technique provides a novel approach for flap advancement and may reduce potential complications involved in releasing incisions. The true benefit of UMST needs to be evaluated in future studies.

Clinical Outcomes of Socket Preservation Using Bovine-Derived Xenograft Collagen and Collagen Membrane Post-Tooth Extraction: A 6-Month Randomized Controlled Clinical Trial

The aim of this study was to evaluate the clinical remodeling of the alveolar socket following the application of bovine-derived xenograft collagen and collagen membrane compared to natural spontaneous healing during the first 6 months following tooth extraction. A total of 20 patients with 20 fresh alveolar sockets were randomly allocated into a test or control group. After a 6-month follow-up period, surgical reentry was performed and implants were placed. Significant statistical differences were recorded in terms of vertical and horizontal bone changes between the test and control groups. Within the limitations of this study, socket preservation procedures may provide more favorable conditions for subsequent implant placement.

Volumetric comparison of autogenous bone and tissue-engineered bone replacement materials in alveolar cleft repair: a systematic review and meta-analysis

The goal of reconstruction of the alveolar cleft in patients with cleft lip and palate is to improve the quality of tissue, the structural stability, and increase the volume of bone. This study is a systematic review with meta-analysis of volumetric bony filling using autogenous bone and various tissue-engineered bone substitutes. We made an electronic search on MEDLINE, EMBASE, SCOPUS, WEB OF SCIENCE, "grey" publications (materials and research produced by organisations outside traditional channels for commercial or academic publishing and distribution), and relevant cross references according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies that reported the outcomes of volumetric grafting were included in the meta-analysis. Of 1276 studies, 26 were included in the meta-analysis. Pooled analysis of 25 studies that used autogenous bone showed a significant reduction in the volume of the cleft equivalent to 62.0% bone fill (95% CI 54.3 to 69.6), in contrast to 10 studies that used a tissue-engineered material and reported bone filling of 68.7% (95% CI 54.5 to 82.8). The estimated sizes of pooled effects across studies showed that there was no significant difference between the two major intervention groups (p value 0.901). Our statistical analysis showed that autogenous bone grafts did not differ significantly from tissue-engineered materials in their ability to fill clefts. Systematic review registration: International Prospective Register of Systematic Reviews, PROSPERO (CRD42017065045).

Evaluation of the clinical effectiveness of bioactive glass (S53P4) in the treatment of non-unions of the tibia and femur: study protocol of a randomized controlled non-inferiority trial

BACKGROUND

Treatment of non-union remains challenging and often necessitates augmentation of the resulting defect with an autologous bone graft (ABG). ABG is limited in quantity and its harvesting incurs an additional surgical intervention leaving the risk for associated complications and morbidities. Therefore, artificial bone graft substitutes that might replace autologous bone are needed. S53P4-type bioactive glass (BaG) is a promising material which might be used as bone graft substitute due to its osteostimulative, conductive and antimicrobial properties. In this study, we plan to examine the clinical effectiveness of BaG as a bone graft substitute in Masquelet therapy in comparison with present standard Masquelet therapy using an ABG with tricalciumphosphate to fill the bone defect.

METHODS/DESIGN

This randomized controlled, clinical non-inferiority trial will be carried out at the Department of Orthopedics and Traumatology at Heidelberg University. Patients who suffer from tibial or femoral non-unions with a segmental bone defect of 2-5 cm and who are receiving Masquelet treatment will be included in the study. The resulting bone defect will either be filled with autologous bone and tricalciumphosphate (control group, N = 25) or BaG (S53P4) (study group, N = 25). Subsequent to operative therapy, all patients will receive the same standardized follow-up procedures. The primary endpoint of the study is union achieved 1year after surgery.

DISCUSSION

The results from the current study will help evaluate the clinical effectiveness of this promising biomaterial in non-union therapy. In addition, this randomized trial will help to identify potential benefits and limitations regarding the use of BaG in Masquelet therapy. Data from the study will increase the knowledge about BaG as a bone graft substitute as well as identify patients possibly benefiting from Masquelet therapy using BaG and those who are more likely to fail, thereby improving the quality of non-union treatment.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS), ID: DRKS00013882 . Registered on 22 January 2018.

Treatment outcomes of the simple bone cyst: A comparative study of 2 surgical techniques using artificial bone substitutes

Simple bone cysts (SBCs) are benign lesions of unknown etiology. Because of its high relapse rate, they occasionally need a long period of treatment and restriction of activities in children and adolescent. Although various treatment modalities with variable differing outcomes have been described in the literature, no consensus has been reached regarding the standard treatment. The purpose of this study was to evaluate the outcome of a minimally invasive technique that uses a ceramic hydroxyapatite cannulated pin (HA pin) for the treatment of SBCs.Between 1998 and 2015, we have treated 75 patients with SBCs either with continuous decompression by inserting HA pins after curettage and multiple drilling (group 1, n = 39 patients) or with calcium phosphate cement (CPC) filling after curettage (group 2, n = 36 patients). These patients were retrospectively analyzed for recurrence-free survival (RFS) and factors implicated in SBC recurrence.Seventy-five patients (50 man and 25 females) with a mean age of 17.5 ± 11.6 years and a histopathologically confirmed diagnosis of SBCs were included. The mean follow-up period was 33 ± 25.3 months. RFS were 88% at 1 year and 81% at 5 years. Residual or progressing cysts were observed in 12 patients after the surgery and 10 of them underwent additional surgery. Recurrence rate was significantly higher in patients under the age of 10 years (P = .01), in long bone cysts (P = .01), and in active phase cysts (P = .003) (log-rank test). Multivariate analysis results revealed that age less than 10 years was an independent risk factor of recurrence (P = .04). No significant difference in recurrence rate was observed between groups 1 and 2. However, the mean operating time was significantly shorter in group 1. (62.4 ± 25.6 vs 110.5 ± 48.4 minutes in group 2).Continuous decompression using HA pin is a less invasive surgical technique for the treatment of SBCs compared with CPC filling and has a high healing rate. The relapse rate was still high when the cysts were caused in children aged less than 10 years, located in the long bone, or remained adjacent to the epiphysis.

LEVEL OF EVIDENCE

Level 3, Retrospective comparative study.