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STUDY DESIGN: Systematic literature review. OBJECTIVES: To analyze the evidence available reporting complications in single or two-level anterior cervical discectomy and fusion (ACDF) using a demineralized bone matrix (DBM), hydroxyapatite (HA), or beta-tricalcium phosphate (ß-TCP). METHODS: A systematic review of the literature using PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov databases was performed in August 2020 to identify studies reporting complications in one or two-level ACDF surgery using DBM, HA, or ß-TCP. The study was reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. RESULTS: A total of 1857 patients were included, 981 male and 876 female, across 17 articles; 5 prospective, and 12 retrospectives. We noted heterogeneity among the included studies concerning the study design and combination of graft materials utilized in them. However, we noted a higher incidence of adjacent segment disease (17.7%) and pseudoarthrosis (9.3%) in fusion constructs using DBM. Studies using ß-TCP reported a higher incidence of pseudoarthrosis (28.2%) and implant failures (17.9%). CONCLUSIONS: Degenerative cervical conditions treated with one or two-level ACDF surgery using DBM, HA, or ß-TCP with or without cervical plating are associated with complications such as adjacent segment disease, dysphagia, and pseudarthrosis. However, consequent to the study designs and clinical heterogeneity of the studies, it is not possible to correlate these complications accurately with any specific graft material employed. Further well-designed prospective studies are needed to correctly know the related morbidity of each graft used for achieving fusion in ACDF.

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Bovine bone is an animal-origin matrix rich in type I collagen (COL I) and it necessitates prior demineralization and makes COL I available. This study investigated the ossein-hydroxyapatite physicochemical properties evaluation as a result of processing and solubilization by acids and revealed the bone matrix demineralization and making COL I available. The tibia residue from bovine sources was processed, ground, and transformed into bone matrix powder. The bone matrix was solubilized in acetic acid followed by lactic acid. The bone matrix was evaluated as a result of processing and solubilization by acids: ossein and hydroxyapatite percentages by nitrogen and ash content, mineral content, particle size distribution, Fourier-transformation infrared spectroscopy, x-ray diffraction, and scanning electron microscope. For the obtained residual extracts, pH and mineral content were evaluated. The solubilization by acids affected the ossein-hydroxyapatite physicochemical properties, and the bone matrix solubilized by acetic and lactic acid showed the preservation of the ossein alongside the loss of hydroxyapatite. The processing and the solubilization by acids were revealed to be a  alternative to bone matrix demineralization and enabling the accessibility of bone COL I. PRACTICAL APPLICATION: Bovine bone is an abundant type I collagen source, but processing maneuvers and demineralization effect present limitations due to the rigidity of the structural components. Exploring methodologies to process and demineralize will allow type I collagen to be obtained from the bone source, and direct and amplify the potentialities in the chemical and food industries. The research focused on bone sources and collagen availability holds paramount significance, and promotes repurposing agribusiness residues and development of protein-base products.

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This comparative study investigated the tissue regeneration and inflammatory response induced by xenografts comprised of hydroxyapatite (HA) and demineralized bone matrix (DBM) extracted from porcine (P) and bovine (B) sources. First, extraction of HA and DBM was independently conducted, followed by chemical and morphological characterization. Second, mixtures of HA/DBM were prepared in 50/50 and 60/40 concentrations, and the chemical, morphological, and mechanical properties were evaluated. A rat calvarial defect model was used to evaluate the tissue regeneration and inflammatory responses at 3 and 6 months. The commercial allograft DBM Puros® was used as a clinical reference. Different variables related to tissue regeneration were evaluated, including tissue thickness regeneration (%), amount of regenerated bone area (%), and amount of regenerated collagen area (%). The inflammatory response was evaluated by quantifying the blood vessel area. Overall, tissue regeneration from porcine grafts was superior to bovine. After 3 months of implantation, the tissue thickness regeneration in the 50/50P compound and the commercial DBM was significantly higher (~99%) than in the bovine materials (~23%). The 50/50P and DBM produced higher tissue regeneration than the naturally healed controls. Similar trends were observed for the regenerated bone and collagen areas. The blood vessel area was correlated with tissue regeneration in the first 3 months of evaluation. After 6 months of implantation, HA/DBM compounds showed less regenerated collagen than the DBM-only xenografts. In addition, all animal-derived xenografts improved tissue regeneration compared with the naturally healed defects. No clinical complications associated with any implanted compound were noted.

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BACKGROUND: Nowadays, biomaterials used as a scaffold must be easy to deliver in the bone defect area. Extracellular matrix (ECM) hydrogels are highly hydrated polymers that can fill irregular shapes and act as bioactive materials. OBJECTIVE: This work aims to show the effects of ECM hydrogels derived from bovine bone (bECMh) on proliferation, cytotoxicity and expression of pro-inflammatory cytokines in three cells types involved in tissue regeneration, as well as biocompatibility in vivo. METHODS: In vitro, we used an extract of bECMh to test it on macrophages, fibroblasts, and adipose-derived mesenchymal stem cells (AD-MCSs). Cell proliferation was measured using the MTT assay, cytotoxicity was measured by quantifying lactate dehydrogenase release and the Live/Dead Cell Imaging assays. Concentrations of IL-6, IL-10, IL-12p70, MCP-1 and TNF-α were quantified in the supernatants using a microsphere-based cytometric bead array. For in vivo analysis, Wistar rats were inoculated into the dorsal sub-dermis with bECMh, taking as reference the midline of the back. The specimens were sacrificed at 24 h for histological study. RESULTS: In vitro, this hydrogel behaves as a dynamic biomaterial that increases fibroblast proliferation, induces the production of pro-inflammatory cytokines in macrophages, among which MCP-1 and TNF-α stand out. In vivo, bECMh allows the colonization of host fibroblast-like and polymorphonuclear cells, without tissue damage or inflammation. CONCLUSIONS: The results indicate that bECMh is a biocompatible material that could be used as a scaffold, alone or in conjunction with cells or functional biomolecules, enhancing proliferation and allowing the filling of bone defects to its further regeneration.

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Objectives: This study evaluated the cellular response of primary osteoblasts exposed to two different presentations of a low-temperature non-sintered deproteinized bovine bone matrix (DBBM). Materials and methods: Six different baths of a commercially available DBBM block (Bonefill® Porous Block) and one of DBBM granule (Bonefill® Porous) were evaluated to identify the mineral structure and organic or cellular remnants. Samples of the same baths were processed in TRIZOL for RNA extraction and quantification. For the immunologic cell reaction assay, primary human osteoblasts (pOB) were exposed to DBMM block (pOB + B) or granules (pOB + G), or none (control) for 1, 3, or 7 days of cell cultivation. Expression of proinflammatory cytokines by pOB was evaluated by crosslinked ELISA assay. In addition, total DNA amount, as well as cell viability via LDH evaluation, was assessed. Results: Organic remnants were present in DBBM blocks; 45.55% (±7.12) of osteocytes lacunae presented cellular remnants in blocks compared to 17.31% (±1.31) in granules. In three of five batches of blocks, it was possible to isolate bovine RNA. The highest concentration of TGF-ß1 was found in supernatants of pOB + G on day 7 (218.85 ± 234.62 pg/mL) (p < 0.05), whereas pOB + B presented the lowest amount of TGF-ß1 secretion at the end of evaluation (30.22 ± 14.94 pg/mL, p < 0.05). For IL-6 and OPG, there was no statistical difference between groups, while pOB + G induced more IL-8 secretion than the control (3.03 ± 3.38 ng/mL, p < 0.05). Considering the kinetics of cytokine release during the study period, all groups presented a similar pattern of cytokines, estimated as an increasing concentration for IL-6, IL-8, and OPG during cultivation. Adherent cells were observed on both material surfaces on day 7, according to H&E and OPN staining. Conclusion: Neither tested material induced a pronounced inflammatory response upon osteoblast cultivation. However, further studies are needed to elucidate the potential influence of organic remnants in bone substitute materials on the regeneration process.

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Objective: To determine the regenerating effect of hyaluronic acid on circumferential bone defects in albino Wistar rats. Material and Methods: An experimental type study was designed and carried out with 15 albino male Wistar rats, 4 months old and weighing between 250 and 350 grams. Two circumferential bone defects 3mm in diameter and 0.8mm deep were created in the calvaria of the parietal bone (on both sides of the midline). One defect was filled with a demineralized bone matrix (control group); while the other defect was filled with the combination of a demineralized bone matrix plus hyaluronic acid (experimental group). Five experimental rats were euthanized at 30, 60 and 90 days after surgery and they were histologically evaluated following the parameters proposed by Heiple. Results: The experimental group presented a better degree of bone regeneration at 30 and 60 postoperative days. Conclusion: Hyaluronic acid is effective in bone regeneration of circumferential bone defects.

Objetivo: Determinar el efecto regenerador del ácido hialurónico en defectos óseos circunferenciales en ratas albinas Wista. Material y Métodos: Se diseñó un estudio de tipo experimental y se trabajó con 15 ratas albinas Wistar (todas macho) de 4 meses de edad y con un peso entre 250 a 350 gr. Se crearon en todas 2 defectos óseos circunferenciales de 3mm de diámetro y 0.8 mm de profundidad en la calota del hueso parietal (a ambos lados de la línea media). Un defecto fue rellenado con una matriz ósea desmineralizada (grupo control); mientras que el otro defecto fue rellenado con la combinación de una matriz ósea desmineralizada más el ácido hialurónico (grupo experimental). Se realizó la eutanasia a 05 ratas de experimentación a los 30, 60 y 90 días postquirúrgicos y se evaluaron histológicamente siguiendo los parámetros propuestos por Heiple. Resultados: El grupo experimental presentó un mejor grado de regeneración ósea en los 30 y 60 días postoperatorios. Conclusiones: El ácido hialurónico es eficaz en la regeneración ósea de defectos óseos circunferenciales.

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INTRODUCTION: Clinical and experimental studies have been attesting the deleterious effects of smoking mainly due to the stimulation of osteoclastogenesis and inhibition of osteoblastogenesis. However the physiological mechanisms that can explain these changes are not fully understood. AIMS: To evaluate the trabecular bone resorption effect caused by long-term exposure to cigarette smoke and the action of cytokines and reactive oxygen species involved in this process. METHODS: Sixty young adult C57BL/6 mice were allocated to two groups: control, 30 animals exposed to filtered air for 1, 3 and 6 months; and smoke, 30 animals exposed to cigarette smoke for 1, 3 and 6 months. Femoral and tibial extraction was performed to evaluate the bone mineral matrix, bone cytokines (Receptor activator of nuclear factor-kappa B ligand - RANKL and Osteoprotegerin - OPG) and oxidative stress markers (Thiobarbituric acid reactive substances - Tbars). RESULTS: Exposure to cigarette smoke (CS) generated changes in bone structural parameters in the 6th month of follow-up, demonstrating an evident bone loss; reduction in OPG/RANKL ratio from the 3rd month on and increase in Tbars in the first month, both closely related to the increase in osteoclastogenic activity and bone resorption. CONCLUSION: These findings reinforce the importance of CS-induced oxidative stress in bone compromising the bone cellular activities with a consequent impairment in bone turn over and changes in bone structure.

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OBJECTIVES: This animal study was conducted to evaluate the osteocyte index in the peri-implant bone around immediately restored implants under static lateral overload. MATERIAL AND METHODS: Seven mongrel dogs received three implants on each side of the mandible. Forty-two implants were distributed into three groups (14 implants per group); each animal received two implants connected to a 4.5-mm opened expansion device (experimental group); in the other mandible side, two implants were connected into an expansion device without activation (control group); one implant each side of the mandible was left submerged (unload group). After 4 months under daily mechanical and chemical plaque control, the animals were euthanized; dental implants and surrounding bone were removed and processed to obtain thin ground sections. Histomorphometry was used to evaluate the osteocyte index in the peri-implant bone contact to implant. RESULTS: A higher, statistically significant mean number of osteocytes × 10-5 µm2 (54.74 ± 23.91) was found in the control group compared with the test group (22.57 ± 22.55) (p = 0.0221). The correlation between percentage of bone-implant contact and osteocyte index for submerged implants was not statistically significant (p = 0.2667), whereas the value for immediately loaded implants was statistically significant (p = 0.0480). CONCLUSION: The lower number of osteocytes in the peri-implant bone around overloaded implants could be related to the need for functional adaptation of the bone tissue to overloading and to the hypothesized involvement of the osteocytes in the maintenance of the bone matrix in the control group. CLINICAL RELEVANCE: Osteocytes play a pivotal role in bone adaptation to mechanical loading, and the osteocyte network has been regarded as being the main mechanosensory mechanism.

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ABSTRACT Purpose To analyze and compare the reactions at the interface between the composite, composed of fragmented heterologous mineralized bone matrix (MOMHF) and polymethylmethacrylate (PMMA), and the rabbit's tibias, through macroscopic evaluation and scanning electron microscopy (SEM) in different periods. Methods In this study, 12 New Zealand adult rabbits were used (E1: n = 3, E2: n = 3, E3: n = 3 and E4: n = 3). They had the right tibial defects filled with composite and were evaluated immediately after surgery and at 30, 60, 90, and 120 days. Results The composites were incorporated and integrated into the recipient beds in 100% of the cases, defined by the MOMHF osseointegration and the PMMA fibrointegration, with no sign of infection, migration, or rejection. Conclusions The behavior of the composites in the recipient beds demonstrates that these biomaterials have the potential to be used in bone defect repairs, offering, thus, better quality of life to the orthopedic patient.

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Smoking is the main risk factor for the development of chronic obstructive pulmonary disease (COPD) and is known to have deleterious effects on bone metabolism. However, the effects on bone collagen matrix during the development of COPD are unclear. The aim of this study was to evaluate the temporal effect of cigarette smoke exposure on bone type I collagen during COPD development in a cigarette smoke-induced model. C57BL/6 mice were allocated to three groups: control (C), animals exposed to filtered air for 1, 3 and 6 months; cigarette smoke (S), animals exposed to cigarette smoke for 1, 3 and 6 months; provisional smoking (PS), animals exposed to cigarette smoke for 3 months, followed by another 3 months of filtered air exposure. Evaluation of the respiratory mechanics and alveolar enlargement were performed. Femoral and tibial extraction was also performed to evaluate the type I collagen by immunofluorescence and COL1A1 gene expression. Exposure to cigarette smoke led to an alveolar enlargement and progressive reduction in lung tissue resistance and elastance, progressive reduction of type I collagen and reduction in COL1A1 gene expression. Although we did not observe any improvement in the functional and histological parameters in the provisional smoking group, we detected an increase in COL1A1 gene expression. A worsening in bone collagen matrix is part of the initial physiopathological events during COPD development and the smoking cessation induced an evident recovery of COL1A1 expression, possibly to attempt at tissue repair.

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BACKGROUND: Radiotherapy used in tumor treatment compromises vascularization of bone tissue. Hyperbaric oxygenation (HBO) increases oxygen availability and improves vascularization, minimizing the deleterious effects of ionizing radiation (IR). Therefore, the aim of this study was to evaluate HBO therapy effect on bone macroscopy, composition and biomechanical properties after IR damage. METHODS: Twenty male Wistar rats weighing 300 ± 20 g (10 weeks of age) were submitted to IR (30 Gy) to the left leg, where the right leg was not irradiated. After 30 days, ten animals were submitted to HBO therapy, which was performed daily for 1 week at 250 kPa for 90-min sessions. All animals were euthanized 37 days after irradiation and the tibia were separated into four groups (n = 10): from animals without HBO - right tibia Non-irradiated (noIRnoHBO) and left tibia Irradiated (IRnoHBO); and from animals with HBO - right tibiae Non-irradiated (noIRHBO) and left tibia Irradiated (IRHBO). The length (proximal-distal) and thickness (anteroposterior and mediolateral) of the tibiae were measured. Biomechanical analysis evaluated flexural strength and stiffness. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) was used to calculate the amide I ratio, crystallinity index, and matrix to mineral ratios. RESULTS: In the macroscopic and ATR-FTIR analysis, the IRnoHBO showed lower values of length, thickness and amide I ratio, crystallinity index and matrix to mineral ratios compared to noIRnoHBO (p < 0.03). IRnoHBO showed no statistical difference compared to IRHBO for these analyses (p > 0.05). Biomechanics analysis showed that the IRnoHBO group had lower values of flexural strength and stiffness compared to noIRnoHBO and IRHBO groups (p < 0.04). In addition, the noIRHBO group showed higher value of flexural strength when compared to noIRnoHBO and IRHBO groups (p < 0.02). CONCLUSIONS: The present study concluded that IR arrests bone development, decreases the collagen maturation and mineral deposition process, thus reducing the flexural strength and stiffness bone mechanical parameters. Moreover, HBO therapy minimizes deleterious effects of irradiation on flexural strength and the bone stiffness analysis.

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Objective: The objective of this study was to evaluate the action of soy isoflavones (ISO) and 17ß-estradiol on collagen I (CollI) and sulfated glycosaminoglycans (GAGs) in the bone matrix of diabetic rats.Methods: Sixty adult female rats (Rattus norvegicus albinus) underwent ovariectomy, and then were randomized into six groups of 10 animals each: GI, sham control ovariectomized animals; GII, sham control diabetic (DM) ovariectomized animals; GIII, control ovariectomized animals receiving propylene glycol vehicle; GIV, control ovariectomized DM animals receiving propylene glycol vehicle; GV, ovariectomized DM animals treated with ISO (150 mg/kg by gavage); and GVI, ovariectomized DM animals treated with estrogen (17ß-estradiol, 10 mg/kg, subcutaneously). 17ß-Estradiol was used as a positive control when compared with ISO. To obtain significant depletion of the estrogen levels and subsequent bone loss, a postsurgical period of 90 days was observed. Treatments occurred during 30 consecutive days. After euthanasia, shafts of the animals' femurs were immersed in liquid nitrogen for molecular biology analysis, and the distal femurs were removed and processed for paraffin embedding.Results: ISO (GV) and 17ß-estradiol (GVI) improved bone formation, increasing GAGs and CollI formation when compared to the control group (GIV) (p < 0.05).Conclusions: ISO and 17ß-estradiol contribute to the decrease of bone loss in diabetic rats.

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BACKGROUND: The aim of this study was to evaluate the ionizing radiation (IR) effects on rat bone 30 and 60 days after irradiation. METHODS: Wistar rats were submitted to IR (30 Gy) on the left leg and were euthanized after 30 and 60 days. The legs were divided into four groups according to the treatment and euthanization time: C30 and C60 (right leg-without IR), IR30 and IR60 (left leg-with IR). RESULTS: CT analysis showed more radiodensity in C60 compared with other groups, and IR60 showed more radiodensity than IR30. In histomorphometric analysis, C30 showed lower bone matrix values compared with IR30 and C60. Lacunarity analyses showed more homogeneous bone channel distribution in C30 than IR30. ATR-FTIR showed decrease in ratio of mature and immature crosslinks in IR30 compared with C30. Crystallinity Index was decrease in IR60 compared with C60. The Amide III + Collagen/HA ratio was increased in C60 compared with C30; however this ratio decreased in IR60 compared with IR30. Biomechanical analysis showed lower values in IR groups in both time. CONCLUSIONS: IR damaged bone quality and decreased stiffness. Moreover, the results suggested that the deleterious effects of IR increased in the late time points.

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Abstract Aim: The present study aimed to analyze the effects of N-acetylcysteine supplementation associated with concurrent training on the bone mineral density of spontaneously hypertensive elderly rats. Methods: For the present study, 28 male spontaneously hypertensive rats, six months old, were distributed in the following groups: control (C, n=7); control + N-acetylcysteine (CNAC, n=7); concurrent training (T, n=7); and concurrent training+N-acetylcysteine (TNAC, n=7). The concurrent training was composed of aerobic training on a treadmill and resistance training in the same training session, three times a week. Animals of the NAC groups received a dose equivalent to 120 mg/kg/day orally for eight weeks. The animals in the trained groups underwent training for eight weeks. The animals were evaluated at the beginning and end of the experiment. After euthanasia, the tibias and femurs were submitted to bone densitometry analysis in an X-ray dual emission device. Results: Lower weight variation was observed in the trained animals and a reduction in pressure values in all groups, but without a statistical difference (p> 0.05). The animals in the T and TNAC groups presented a better performance in the physical tests (p <0.05). In relation to bone, the NAC groups demonstrated a decrease in femoral bone density when compared to groups C and T. Finally, all experimental groups demonstrated an increase in tibial bone density, but with no statistical difference (p>0.05). Conclusion: The animals in group T demonstrated better performance in the physical tests. In addition, the NAC caused a reduction in the bone mineral density of the femur.

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Abstract Stanozolol (ST) is a synthetic androgen with high anabolic potential. Although it is known that androgens play a positive role in bone metabolism, ST action on bone cells has not been sufficiently tested to support its clinical use for bone augmentation procedures. Objective: This study aimed to assess the effects of ST on osteogenic activity and gene expression in SaOS-2 cells. Material and Methods: SaOS-2 deposition of mineralizing matrix in response to increasing doses of ST (0-1000 nM) was evaluated through Alizarin Red S and Calcein Green staining techniques at 6, 12 and 24 days. Gene expression of runt-related transcription factor 2 (RUNX2), vitamin D receptor (VDR), osteopontin (SPP1) and osteonectin (ON) was analyzed by RT-PCR. Results: ST significantly influenced SaOS-2 osteogenic activity: stainings showed the presence of rounded calcified nodules, which increased both in number and in size over time and depending on ST dose. RT-PCR highlighted ST modulation of genes related to osteogenic differentiation. Conclusions: This study provided encouraging results, showing ST promoted the osteogenic commitment of SaOS-2 cells. Further studies are required to validate these data in primary osteoblasts and to investigate ST molecular pathway of action.

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Osteoporosis is associated with poor dietary habits. Malnutrition is characterized as a deficit on the intake of necessary nutrients that are essential for optimal health maintenance. It is known that malnutrition during the lactation period can affect the offspring. The present study aims to evaluate the chronic effects caused by maternal energy-protein restriction during lactation period in the offspring. At parturition, Wistar rat dams were divided in three groups: (1) Control group (C) - which received a 23 % protein diet without restrictions; (2) Protein-Energy restriction group (PER)- which received a 8 % protein diet; (3) Energy restriction group (ER) which received a 23 % protein diet in limited amounts, according to the ingestion of the second group. Each group had 12 pups. After weaning, all pups received free access to a 23 % protein diet until 180 days and then were euthanized. Their femur was excised, decalcified, histologically processed and analyzed under a microscope. The measurements of the osteon lacunae on the C, ER and PER groups were, respectively: 2.1 µm, 10.9 µm and 14.7 µm (p<0.05). A poor ingestion of proteins and calories during lactation period provoked critical and permanent changes on the bone matrix of the femur, which simulated osteoporosis.

La osteoporosis se asocia con malos hábitos alimenticios. La desnutrición se caracteriza como un déficit en la ingesta de los nutrientes necesarios que son esenciales para un mantenimiento óptimo de la salud. Se sabe que la malnutrición durante el período de lactancia puede afectar a la descendencia. El presente estudio tiene como objetivo evaluar los efectos crónicos causados por la restricción energética-proteína materna durante el período de lactancia en la descendencia. En el parto, las hijas de rata Wistar se dividieron en tres grupos: (1) grupo control (C) - que recibió una dieta con 23 % de proteína sin restricciones; (2) Grupo restricción de energía de proteína (PER) - que recibió una dieta con 8 % de proteína; (3) Grupo restricción de energía (ER) - que recibió una dieta de 23 % de proteína en cantidades limitadas, de acuerdo con la ingestión del segundo grupo. Cada grupo tenía 12 crías. Después del destete, todas las crías recibieron acceso libre a una dieta con 23 % de proteína hasta 180 días y luego fueron sacrificadas. Su fémur fue extirpado, descalcificado, procesado histológicamente y analizado bajo un microscopio. Las mediciones de las lagunas de osteón en los grupos C, ER y PER fueron, respectivamente: 2,1 mm, 10,9 mm y 14,7 mm (p <0,05). Una mala ingesta de proteínas y calorías durante el período de lactancia provocó cambios críticos y permanentes en la matriz ósea del fémur, que simulaba osteoporosis.

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Purpose: To compare bone regeneration in critical-sized defects in rat calvarium using demineralized bone matrix and calcium phosphate cement. Methods: Thirty Wistar rats were divided into 3 groups of 10 animals each. Two defects of 5-mm were made in the parietal bones of each animal. Group I had calcium phosphate cement placed in the experimental defect, Group II had filled with demineralized bone matrix and Group III had with the combination of the matrix and cement in equal parts. All animals had one defect left unfilled to serve as controls. Five animals in each group were sacrificed at 4 and 8 weeks. Histomorphometric analysis was used to quantify the amount of new bone within the defects. Results: The results showed that demineralized bone matrix-treated defects had significantly more new bone at 4 weeks compared to calcium phosphate cement-treated defects (p=0.03) and also had significantly more new bone at 8 weeks compared to unfilled defects (p=0.04). Conclusions: The demineralized bone matrix was superior to calcium phosphate cement in bone regeneration. It seems that calcium phosphate cement acted by inhibiting the osteogenesis when associated with a demineralized bone matrix and this combination should not be recommended.(AU)

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Abstract Purpose: To compare bone regeneration in critical-sized defects in rat calvarium using demineralized bone matrix and calcium phosphate cement. Methods: Thirty Wistar rats were divided into 3 groups of 10 animals each. Two defects of 5-mm were made in the parietal bones of each animal. Group I had calcium phosphate cement placed in the experimental defect, Group II had filled with demineralized bone matrix and Group III had with the combination of the matrix and cement in equal parts. All animals had one defect left unfilled to serve as controls. Five animals in each group were sacrificed at 4 and 8 weeks. Histomorphometric analysis was used to quantify the amount of new bone within the defects. Results: The results showed that demineralized bone matrix-treated defects had significantly more new bone at 4 weeks compared to calcium phosphate cement-treated defects (p=0.03) and also had significantly more new bone at 8 weeks compared to unfilled defects (p=0.04). Conclusions: The demineralized bone matrix was superior to calcium phosphate cement in bone regeneration. It seems that calcium phosphate cement acted by inhibiting the osteogenesis when associated with a demineralized bone matrix and this combination should not be recommended.

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STUDY DESIGN: A narrative review of literature. OBJECTIVE: This manuscript intends to provide a review of clinically relevant bone substitutes and bone expanders for spinal surgery in terms of efficacy and associated clinical outcomes, as reported in contemporary spine literature. SUMMARY OF BACKGROUND DATA: Ever since the introduction of allograft as a substitute for autologous bone in spinal surgery, a sea of literature has surfaced, evaluating both established and newly emerging fusion alternatives. An understanding of the available fusion options and an organized evidence-based approach to their use in spine surgery is essential for achieving optimal results. METHODS: A Medline search of English language literature published through March 2016 discussing bone graft substitutes and fusion extenders was performed. All clinical studies reporting radiological and/or patient outcomes following the use of bone substitutes were reviewed under the broad categories of Allografts, Demineralized Bone Matrices (DBM), Ceramics, Bone Morphogenic proteins (BMPs), Autologous growth factors (AGFs), Stem cell products and Synthetic Peptides. These were further grouped depending on their application in lumbar and cervical spine surgeries, deformity correction or other miscellaneous procedures viz. trauma, infection or tumors; wherever data was forthcoming. Studies in animal populations and experimental in vitro studies were excluded. Primary endpoints were radiological fusion rates and successful clinical outcomes. RESULTS: A total of 181 clinical studies were found suitable to be included in the review. More than a third of the published articles (62 studies, 34.25%) focused on BMP. Ceramics (40 studies) and Allografts (39 studies) were the other two highly published groups of bone substitutes. Highest radiographic fusion rates were observed with BMPs, followed by allograft and DBM. There were no significant differences in the reported clinical outcomes across all classes of bone substitutes. CONCLUSIONS: There is a clear publication bias in the literature, mostly favoring BMP. Based on the available data, BMP is however associated with the highest radiographic fusion rate. Allograft is also very well corroborated in the literature. The use of DBM as a bone expander to augment autograft is supported, especially in the lumbar spine. Ceramics are also utilized as bone graft extenders and results are generally supportive, although limited. The use of autologous growth factors is not substantiated at this time. Cell matrix or stem cell-based products and the synthetic peptides have inadequate data. More comparative studies are needed to evaluate the efficacy of bone graft substitutes overall.

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The aim of this paper was to evaluate through histological analysis of the tissue reaction of deproteinized bovine bone matrix (DBBM) when inserted into the site of intramuscular ectopic sheep. In this study, 16 sheep received 3 groups and these were divided into 2 experimental times: Group 1-sham group, Group 2-particulate autogenous bone and Group 3-DBBM granules. All animals underwent surgical procedures for insertion of materials in an ectopic site (muscles of the lower back and after 3 and 6 months postoperatively, the samples were evaluated by histological analysis. The results indicated that the Sham group showed dense collagen fibers and thin, characterizing fibrosis at 3 and 6 months. In the autograft group there was a significant amount of collagen deposition and decreased inflammation at 6 months postoperatively. Group of DBBM, it was noted the presence of dense connective tissue and surrounding remaining particles was observed the formation of with osteoid characteristic tissue. The DBBM demonstrated biocompatibility, osteoconductivity and small osteogenesis capacity on ectopic site.

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