Demineralized Bone Matrix Products Research Articles

Variability of BMP-2 content in DBM products derived from different long bone.

Demineralized bone matrix (DBM) has been regarded as an ideal bone substitute as a native carrier of bone morphogenetic proteins (BMPs) and other growth factors. However, the osteoinductive properties diverse in different DBM products. We speculate that the harvest origin further contributing to variability of BMPs contents in DBM products besides the process technology. In the study, the cortical bone of femur, tibia, humerus, and ulna from a signal donor were prepared and followed demineralizd into DBM products. Proteins in bone martix were extracted using guanidine-HCl and collagenase, respectively, and BMP-2 content was detected by sandwich enzyme-linked immunosorbent assay (ELISA). Variability of BMP-2 content was found in 4 different DBM products. By guanidine-HCl extraction, the average concentration in DBMs harvested from ulna, humerus, tibia, and femur were 0.613 ± 0.053, 0.848 ± 0.051, 3.293 ± 0.268, and 21.763 ± 0.344, respectively (p < 0.05), while using collagenase, the levels were 0.089 ± 0.004, 0.097 ± 0.004, 0.330 ± 0.012, and 1.562 ± 0.008, respectively (p < 0.05). In general, the content of BMP-2 in long bones of Lower limb was higher than that in long bones of upper limb, and GuHCl had remarkably superior extracted efficiency for BMP-2 compared to collagenase. The results suggest that the origin of cortical bones harvested to fabricate DBM products contribute to the variability of native BMP-2 content, while the protein extracted method only changes the measured values of BMP-2.

Composite demineralized bone matrix nanofiber scaffolds with hierarchical interconnected networks via eruptive inorganic catalytic decomposition for osteoporotic bone regeneration

Demineralized bone matrix (DBM) is one of the standard biomaterials used to fill surgical bone defects in general orthopedic procedures. However, current DBM products come in the form of powder or viscous solutions that fail to mimic the natural hierarchical structure of bone while also using large amounts of valuable material. To overcome this, compact fibrous DBM/polymer (fDBM) composites were prepared via electrospinning. Then, by exploiting the catalytic decomposition of hydrogen peroxide, oxygen pockets are formed in the scaffold imparting it with a hierarchical porous structure similar to bone (Op-fDBM). These pockets created by bubbles of oxygen help give the scaffold a mechanically stable shape while the incorporated DBM supports cell adhesion and growth. In vivo evaluations reveal that fDBM increased bone volume by 41.7 % while Op-fDBM increased bone volume by 68.6 %. Significant increases in regenerated bone volume with the use of minimal amounts of DBM in fiber form go to show the great potential of this work in the field of bone regeneration.

Open-source perfusion system for medium-scale fabrication of demineralized bone matrix chip grafts

Demineralized bone matrix (DBM) is considered one of the most reliable bone tissue grafts for regular surgical use, as it provides a scaffold that is structurally like native bone, and that enhances bone regeneration. However, commercially available DBM products are not suited for surgical restitutions of large bones. Therefore, each Tissue Bank is urged to implement their own demineralization protocol, which usually does not meet the high demand for bone grafting. In this project, we developed an open source system for medium-scale manufacturing of DBM grafts from human cadaveric donors to automate the demineralization protocol and improve its reproducibility. The device consists in (1) unidirectional flow reaction chamber, where the demineralization protocol takes place; (2) automated syringe pump, which controls the reagent́s inlet and vacuum; and (3) reagent dispenser, for the management of the reagents need for the demineralization protocol. Validation of the device included histological analysis, DNA quantification temperature regulation, electrochemiluminescence and colorimetric protocols, followed by the optimization of physicochemical parameters based on Response Surface Methodology. The results showed values of residual lipids and calcium within standardized ranges, and the maintenance of the structural integrity of the DBM, demonstrating the capacity of the system to support the proposed demineralization protocol.

A literature review of commercially available demineralized bone matrix products and their clinical evidence in acute fractures, nonunions, and fusion procedures

Demineralized bone matrix (DBM) is an allograft obtained from human cadaveric bone that has osteoinductive and osteoconductive properties. A wide array of specific DBM products is available, and each has its own biochemical, safety, and efficacy profiles. This study reviews comparison studies of brand-specific DBM products, including Allomatrix (Wright Medical Technology, Memphis, Tennessee), DBX (Depuy Synthes, Suchwil, Switzerland), Grafton (Osteotech, Eatontown, New Jersey), Orthoblast (Integra Orthobiologics, Plainsboro, New Jersey), and Osteosponge (Bacterin International, Belgrade, Montana), in an attempt to propose the most efficacious DBM product for bone grafting of various orthopaedic applications. Secondarily, we evaluate these specific DBM products in their potential use of tibial plateau fractures, which our future clinical research aims to achieve. A definitive gold-standard DBM product is lacking for orthopaedic use because of the scarcity of clinical research comparing specific brand products, limited study sample sizes, and lack of standardization in the creation of DBM products. Level of Evidence: Level III.

In-vivo Performance of Seven Commercially Available Demineralized Bone Matrix Fiber and Putty Products in a Rat Posterolateral Fusion Model.

Introduction: Demineralized bone matrix (DBM) is a widely used bone graft in spinal fusion. Most commercial DBMs are composed of demineralized bone particles (~125–800 microns) suspended in a carrier that provides improved handling but dilutes the osteoinductive component. DBM fibers (DBF) provide improved osteoconductivity and do not require a carrier. It has been suggested that 100% DBF may offer improved performance over particulate-based DBMs with carrier.Study Design: Seven commercially available DBM products were tested in an athymic rat posterolateral fusion model. There were four 100% DBFs, two DBFs containing a carrier, and one particulate-based DBM containing carrier.Objective: The study objectives were to evaluate the in vivo performance: (1) compare fusion rate and fusion maturity of six commercially available DBFs and one particulate-based DBM, and (2) assess the effect of carrier on fusion outcomes for DBFs in a posterolateral fusion model.Methods: The DBF/DBM products evaluated were: StrandTM Family, Propel® DBM Fibers, Vesuvius® Demineralized Fibers, Optium® DBM Putty, Grafton® DBF, Grafton Flex, and DBX® Putty. Single-level posterolateral fusion was performed in 69 athymic rats. Fusion was assessed bilaterally after 4 weeks by manual palpation, radiograph and CT for bridging bone. Fusion mass maturity was assessed with a CT maturity grading scale and by histology. Statistical analysis was performed using Fishers Exact Test for categorical data and Kruskal-Wallis Test for non-parametric data.Results: Strand Family achieved 100% fusion (18/18) by manual palpation, radiographic and CT evaluation, significantly higher than Propel Fibers, Vesuvius Fibers, Optium Putty, and DBX Putty, and not statistically higher than Grafton DBF and Grafton Flex. Strand Family provided the highest fusion maturity, with CT maturity grade of 2.3/3.0 and 89% mature fusion rate. Fusion results suggest a detrimental effect of carrier on fusion performance.Conclusions: There were large variations in fusion performance for seven commercially available DBM products in an established preclinical fusion model. There were even significant differences between different 100% DBF products, suggesting that composition alone does not guarantee in vivo performance. In the absence of definitive clinical evidence, surgeons should carefully consider available data in valid animal models when selecting demineralized allograft options.

Demineralized Bone Matrix Carriers and their Clinical Applications: An Overview.

Reconstruction of massive bone defects is challenging for orthopaedic clinicians, especially in cases of severe trauma and resection of tumors in various locales. Autologous iliac crest bone graft (ICBG) is the “gold standard” for bone grafting. However, the limited availability and complications at donor sites resulted in seeking other options like allografts and bone graft substitutes. Demineralized bone matrix (DBM) is a form of allograft using acidic solution to remove mineral components, while leaving much of the proteinaceous components native to bone, with small amounts of calcium‐based solids, inorganic phosphates, and some trace cell debris. It is an osteoconductive and osteoinductive biomaterial and is approved as a medical device for use in bone defects and spinal fusion. To pack consistently into the defect sites and stay firmly in the filling parts, DBM products have various forms combined with biocompatible viscous carriers, including sponges, strips, injectable putty, paste, and paste infused with chips. The present review aims to summarize the properties of various kind of viscous carriers and their clinical use combined with DBM in commercially available products. Given DBM'mercially available products. Given DBM;s long clinical track record and commercial accessibility in standard forms, opportunities to further develop and validate DBM as a versatile bone biomaterial in orthopaedic repair and regenerative medicine contexts are attractive.

Local effect of zoledronic acid on new bone formation in posterolateral spinal fusion with demineralized bone matrix in a murine model.

Posterolateral spinal fusion is a common orthopaedic surgery performed to treat degenerative and traumatic deformities of the spinal column. In posteriolateral spinal fusion, different osteoinductive demineralized bone matrix products have been previously investigated. We evaluated the effect of locally applied zoledronic acid in combination with commercially available demineralized bone matrix putty on new bone formation in posterolateral spinal fusion in a murine in vivo model. A posterolateral sacral spine fusion in murine model was used to evaluate the new bone formation. We used the sacral spine fusion model to model the clinical situation in which a bone graft or demineralized bone matrix is applied after dorsal instrumentation of the spine. In our study, group 1 received decortications only (n=10), group 2 received decortication, and absorbable collagen sponge carrier, group 3 received decortication and absorbable collagen sponge carrier with zoledronic acid in dose 10µg, group 4 received demineralized bone matrix putty (DBM putty) plus decortication (n=10), and group 5 received DBM putty, decortication and locally applied zoledronic acid in dose 10µg. Imaging was performed using MicroCT for new bone formation assessment. Also, murine spines were harvested for histopathological analysis 10weeks after surgery. The surgery performed through midline posterior approach was reproducible. In group with decortication alone there was no new bone formation. Application of demineralized bone matrix putty alone produced new bone formation which bridged the S1-S4 laminae. Local application of zoledronic acid to demineralized bone matrix putty resulted in significant increase of new bone formation as compared to demineralized bone matrix putty group alone. A single local application of zoledronic acid with DBM puttyduring posterolateral fusion in sacral murine spine model increased significantly new bone formation in situ in our model. Therefore, our results justify further investigations to potentially use local application of zoledronic acid in future clinical studies.

The available evidence on demineralised bone matrix in trauma and orthopaedic surgery: A systematic review.

ObjectivesThe aim of this systematic literature review was to assess the clinical level of evidence of commercially available demineralised bone matrix (DBM) products for their use in trauma and orthopaedic related surgery.MethodsA total of 17 DBM products were used as search terms in two available databases: Embase and PubMed according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement. All articles that reported the clinical use of a DBM-product in trauma and orthopaedic related surgery were included.ResultsThe literature search resulted in 823 manuscripts of which 64 manuscripts met the final inclusion criteria. The included manuscripts consisted of four randomised controlled trials (level I), eight cohort studies (level III) and 49 case-series (level IV). No clinical studies were found for ten DBM products, and most DBM products were only used in combination with other grafting materials. DBM products were most extensively investigated in spinal surgery, showing limited level I evidence that supports the use Grafton DBM (Osteotech, Eatontown, New Jersey) as a bone graft extender in posterolateral lumbar fusion surgery. DBM products are not thoroughly investigated in trauma surgery, showing mainly level IV evidence that supports the use of Allomatrix (Wright Medical, London, United Kingdom), DBX (DePuy Synthes, Zuchwil, Switzerland), Grafton DBM, or OrthoBlast (Citagenix Laval, Canada) as bone graft extenders.ConclusionsThe clinical level of evidence that supports the use of DBM in trauma and orthopaedic surgery is limited and consists mainly of poor quality and retrospective case-series. More prospective, randomised controlled trials are needed to understand the clinical effect and impact of DBM in trauma and orthopaedic surgery.Cite this article: J. van der Stok, K. A. Hartholt, D. A. L. Schoenmakers, J. J. C. Arts. The available evidence on demineralised bone matrix in trauma and orthopaedic surgery: A systemati c review. Bone Joint Res 2017;6:423–432. DOI: 10.1302/2046-3758.67.BJR-2017-0027.R1.

The role of orthobiologics in foot and ankle surgery: Allogenic bone grafts and bone graft substitutes.

Orthobiologics are biological substances that are used therapeutically for their positive effects on healing skeletal and soft-tissue injuries. The array of orthobiological products currently available to the foot and ankle surgeon is wide, and includes bone allografts, bone substitutes, growth factors, and chondral scaffolds. Nonetheless, despite the surge in interest and usage of orthobiologics, there remains a relative paucity of research addressing their specific applications in foot and ankle surgery. In this review, we attempt to provide an overview of the literature on commonly available allogenic bone grafts and bone substitutes.There is Level II, III and IV evidence addressing allogenic bone grafts in primary arthrodesis and osteotomy procedures in foot and ankle surgery, which compares favourably with autogenic bone grafts in terms of fusion rates and clinical outcomes (often with fewer complications), and supports a Grade B recommendation for its use.Pertaining to bone substitutes, the multiplicity of products, coupled with a lack of large prospective clinical trials, makes firm recommendations difficult. Level II and IV studies of calcium phosphate and calcium sulphate products in displaced intra-articular calcaneal fractures have found favourable results in addressing bone voids, maintaining reduction and promoting union, meriting a Grade B recommendation. Evidence for TCP is limited to level IV studies reporting similarly good outcomes in intra-articular calcaneal fractures, warranting a Grade C recommendation. The use of demineralised bone matrix products in hindfoot and ankle fusions has been described in Level II and III studies, with favourable results in achieving fusion and good clinical outcomes, supporting a Grade B recommendation for these indications.Overall, despite the general lack of high-level evidence in foot and ankle surgery, allogenic bone grafts and bone substitutes continue to hold front-line roles in treating the bone defects encountered in trauma, tumour, and deformity correction surgery. However, more investigation is required before firm recommendations can be made.Cite this article: EFORT Open Rev 2017;2:272–280. DOI: 10.1302/2058-5241.2.160044

Review of commercially available demineralized bone matrix products for spinal fusions: A selection paradigm.

Background:Spinal fusions are commonly performed in the US each year for various spinal pathologies. There are multiple commercially available graft material options for these procedures, including an abundance of demineralized bone matrix (DBM) products.Methods:This study reviews, clearly organizes, and puts forth meaningful information on select biological and physical properties of several commercially available DBM products. In addition, we provide an alternative classification method of DBM products by carrier.Results:This review takes a closer look at the commercial and distributor practices of these products and companies in order to increase transparency between the consumer and source companies.Conclusions:We propose a novel patient-centered approach to DBM product selection. This requires prioritizing patient safety, product effectiveness, and product transparency. This review offers a practical paradigm to facilitate informed product choice for surgeons and hospital systems alike.

Use of demineralized bone matrix in the extremities.

Autologous bone graft is considered as the gold standard for all indications for bone grafting procedures but the limited availability and complications in donor site resulted in seeking other options like allografts and bone graft substitutes. Demineralized bone matrix (DBM) is an allograft product with no quantity limitation. It is an osteoconductive material with osteoinductive capabilities, which vary among different products, depending on donor characteristics and differences in processing of the bone. The purpose of the present review is to provide a critical review of the existing literature concerning the use of DBM products in various procedures in the extremities. Clinical studies describing the use of DBM alone or in combination with other grafting material are available for only a few commercial products. The Level of Evidence of these studies and the resulting Grades of Recommendation are very low. In conclusion, further clinical studies of higher quality are required in order to improve the Recommendation Grades for or against the use of DBM products in bone grafting procedures.

Histological remodelling of demineralised bone matrix allograft in posterolateral fusion of the spine – an ex vivo study

BackgroundDemineralised bone matrix (DBM) has shown to be effective in enhancing posterior fusion of the spine. Several animal studies and clinical investigations in humans showed its successful remodelling. The use of allogenic matrix may decrease the need of autologous bone graft and therefore helps prevent corresponding donor site morbidity. Since DBM products are very expensive, the question arises, whether it is completely remodelled into new bone, and therefore truly is comparable to autologous cancellous bone graft. To our knowledge there is no report of a consecutive series of patients where ex vivo histological analysis after postero-lateral fusion of the spine was performed.MethodsOsseous biopsies of nine consecutive patients who underwent postero-lateral fusion of the spine for trauma were obtained at the time of elective removal of the hardware. Histological samples were then analyzed on ground and thin sections stained with toluidine blue and von Kossa stainings.ResultsTime span between index operation and removal of the metal ranged between 6 and 18 month. Histological analysis showed good incorporation and overall remodelling of DBM into new bone in all patients. No foreign body reaction was visible and new bone formation progressed time dependently with DBM in situ. Four out of nine patients showed more than 50% new bone formation after one year.ConclusionDBM shows good overall remodelling properties in histological analysis and therefore seems to be an effective adjunct in postero-lateral fusion of the spine. Furthermore, DBM substitution increases over time.

Characterization of the inflammatory response to four commercial bone graft substitutes using a murine biocompatibility model

Bone grafting is utilized in nearly all orthopedic subspecialties and in most anatomic regions. Bone graft substitutes have the potential to offer similar efficacy as autogenous grafts without the morbidity of harvest. Several studies have noted the efficacy of new-generation bone substitute products, but few studies have evaluated their safety. This study characterizes and quantifies the inflammatory reaction to four different commercially available bone graft substitutes, which were examined using the in vivo murine air pouch biocompatibility model. One coralline hydroxyapatite product was chosen as an example of a purely osteoconductive material. Three demineralized bone matrix products were chosen to represent products that are both osteoconductive and osteoinductive. Samples were implanted in a murine air pouch and harvested after 14 days in situ. Pouch fluid was extracted, mRNA isolated, and reverse transcription polymerase chain reactions carried out to detect interleukin-1 gene expression as a marker for inflammation. In addition, multiple histological characteristics were examined to quantify cellular responses to the implanted materials. All bone graft substitutes induced a significant inflammatory response compared with negative controls. Histology and polymerase chain reaction data indicated that the level of inflammatory reaction was elevated in materials with a higher demineralized bone matrix to carrier proportion. The hydroxyapatite product generated a low inflammatory reaction. In conclusion, this study used an in vivo model of biocompatibility to demonstrate that a significant inflammatory reaction occurs when using implanted bone graft substitutes. When choosing a bone grafting method, surgeons should consider both the efficacy and safety of methods and materials used. Further studies are necessary to determine the ideal bone graft material to maximize efficacy while minimizing morbidity.

&lt;i&gt;In Vitro&lt;/i&gt; and &lt;i&gt;In Vivo&lt;/i&gt; Evaluation of a Calcium Phosphate and Demineralized Bone Matrix Composite Biomaterial

A new class of osteoconductive and osteoinductive combination biomaterials composed of calcium phosphate cement (CPC), demineralized bone matrix (DBM) and a water-soluble viscosity modifier were prepared and characterized in-vitro and in-vivo. In previous studies, a range of combinations formulations were tested in order to compare their performance characteristic. In-vitro characterization results show that the mechanical strength is decreased when the amount of DBM increases. However, DBM does not affect the CPC’s ability to set hard and convert to nanocrystalline apatitic calcium phosphate, which shares the chemical structure of natural bone as seen in x-ray diffraction. It is known that the DBM alone is osteoinductive. In-vivo osteoinductivity testing of the formulations in an intramuscular, athymic rat model demonstrated that the combination material is also osteoinductive. Two formulations were chosen for in-vivo efficacy testing based on the results of in-vitro and in-vivo characterization. These formulations were studied using rabbit critical-sized femoral core defect model. The formulations were composed of DBM with particle sizes of 250 to 710 μm, carboxymethyl-cellulose (CMC) as the viscosity modifier and weight percent compositions of 50% DBM/ 45% CPC/ 5% CMC and 60% DBM/ 30% CPC/ 10% CMC. Bone integration and healing was graded at 6, 12, and 24 weeks. The two formulations were compared to the gold standard autograft at 12 weeks and to an empty defect as the negative control at 24 weeks. Based on micro-computed topography (μCT), both formulations allowed for continuity of bone throughout the defect region at all time points. No differences in dense area fraction were seen between two formulations at 6 weeks (p = 0.8661). There was no significant statistical difference between the two formulations and autograft at 12 weeks (p = 0.2467). At 24 weeks, both formulations had significantly higher dense area fractions than empty controls (p = 0.0001). Histologically, the biology of the treatment areas appeared to have returned to normal by 24 weeks with CPC appearing to be the principal osteogenic inducer. In conclusion, these combinations of CPC and DBM offers significant advantages (handling, mechanical properties and osteoinductivity) over current DBM products and can be an effective alternative to autograft in healing of bone defects.

Biomechanical and Radiographic Comparison of Demineralized Bone Matrix, and a Coralline Hydroxyapatite in a Rabbit Spinal Fusion Model

The use of bone grafts is an essential component in spinal fusion. Autologous bone has been shown to result in long-term stable arthrodesis between spinal motion segments. However, autograft can be associated with significant morbidity and a limited supply. Alternatives, such as allogeneic demineralized bone matrix (DBM), are a potential source and supplement to autograft bone. The current study compares the ability of a DBM product (BioSet RT) and a coralline hydroxyapatite (Pro Osteon 500R), for inducing spinal fusion in a rabbit model. BioSet RT, alone or in combination with autograft, and Pro Osteon 500R were implanted in the posterior lateral inter-transverse process region of the rabbit spine. The spines were evaluated at 18 weeks for fusion of the L4-L5 transverse processes using a total of 33 skeletally mature male rabbits; 4 naïve animals were also included in the study. Samples were evaluated radiographically, histologically, by palpation, and through mechanical strength testing. Radiographical, histological, and palpation measurements demonstrated the ability of BioSet RT to induce new bone formation and bridging fusion comparable to autograft. This material performed well alone or in combination with autograft material. Despite significantly higher biomechanical testing results, minimal bone formation and fusion was recorded for the Pro Osteon 500R-treated group. This in vivo study demonstrates the ability of BioSet RT to induce new bone formation, and there was a clear relationship between bridging bone and mechanical strength.

In vitro testing of the osteoinductive potential of different bony allograft preparations

Bony allografts are used frequently in the clinic for bone defect filling, however, less comparative data concerning their osteoinductive potential are available. The purpose of the present study was the comparative analysis of different allograft preparations. From five donors, we investigated fresh-frozen cancellous bone (native), peracetic acid–ethanol sterilized (PES) cancellous bone, cortical bone and demineralised bone matrix (DBM). In addition, two commercially available DBM products from five different donors were analyzed: Allomatrix® (Wright Medical Technology Inc.) and DBX putty® (Synthes GmbH). For positive control and as a clinically used growth factor, BMP-2 was chosen. To investigate the osteoinductivity C2C12 cells were cultured with the different materials and the effect on cell proliferation and alkaline phosphatase activity were measured. Proliferation was significantly enhanced by the native cancellous bone, Allomatrix, and BMP-2 and decreased by the PES-processed cancellous bone. The osteogenic differentiation was significantly enhanced by BMP-2 and the two commercial DBM products and decreased by PES-sterilized cancellous bone. All tested materials revealed a high donor-dependent variability. This is the first comparative study on the osteoinductivity of bony allografts frequently used in clinic.

Effects of e‐beam radiation, storage, and hydration on osteoinductivity of DBM/AM composite

E-beam irradiation is often used to sterilize medical devices including demineralized bone matrix (DBM) products. In this study, the effect of e-beam on osteoinductivity of a DBM product in hydrous and anhydrous configurations has been evaluated at 0-, 6- and 12-month ambient storage using a nude rat muscle pouch model. The thermal and structural stabilities of DBM and acellular dermal matrix (AM) composites were analyzed using differential scanning calorimetry (DSC) and trypsin digestion assay. Both hydrous and anhydrous DBM/AM composites exhibited osteoinductivity after e-beam irradiation of 15 kGy. After 12-month ambient storage, the osteoinductivity of hydrous DBM/AM was diminished, whereas the anhydrous DBM/AM retained its osteoinductive potential. However, the DSC and trypsin analysis revealed that the DBM in anhydrous DBM/AM was more vulnerable to damage from e-beam irradiation than its hydrous counterpart. This study has found that although the anhydrous DBM has more structural damage than hydrous DBM from e-beam irradiation, it has retained its osteoinductivity better after 1-year ambient storage.

90. Variability among 10 Production Lots of a Single Demineralized Bone Matrix Product

90. Variability among 10 Production Lots of a Single Demineralized Bone Matrix Product

Safety and efficacy of commercially available demineralised bone matrix preparations: A critical review of clinical studies

Demineralised bone matrix (DBM), a form of allograft, possesses the properties of osteoinductivity and osteoconductivity. A large body of data obtained from extensive preclinical studies have clearly supported the utility of DBM in human clinical settings. However, it is now recognized that various DBM configurations may differ considerably with regard to their bone inductive activity. Several factors could account for such variability, including the biologic properties of the graft, the host environment, and the methods of allograft preparation. The differing efficacy of DBM products may also depend on differences in particle size and shape, donor selection criteria, protocols for collection and storage, as well as DBM carrier materials. Several comparative studies have confirmed the differences in the osteoinductive potential of various DBM preparations. The purpose of the present review is to provide a critical overview of the current applications of DBM in a clinical setting.

A novel application of high-dose (50 kGy) gamma irradiation for demineralized bone matrix: effects on fusion rate in a rat spinal fusion model

Background context The safety of allograft material has come under scrutiny because of recent reports of allograft-associated bacterial and viral infections in tissue recipients. Gamma irradiation, although being one of the most effective ways of terminal sterilization, has been shown to affect the biomechanical properties of allograft bone. It may also have detrimental effects on the osteoinductivity of allograft material such as demineralized bone matrix (DBM) by the denaturation of proteins because of heat generated by irradiation. Sterilization of DBM material is an important variable in processing graft materials. This is considered to be one of the factors leading to different fusion rates observed with different commercially available DBM products, as the sterilization procedure itself may affect the osteoinductivity of the material. Currently, there is no ideal sterilization technique that limits the detrimental effect on osteoinductivity and fusion rates. Purpose To evaluate the effects of a range of hydrogen peroxide exposures with or without the controlled high-dose gamma irradiation after processing with radioprotectant solutions (Clearant radiation sterilization procedure) on the fusion rates of human DBM. Study design A prospective in vivo animal study. Methods Eighty mature athymic nude female rats were used for this study, which formed 10 equal groups. Human DBM exposed to hydrogen peroxide for different time periods (0, 1, 6, and 24 hours) was divided into two major subgroups. One group was further treated with controlled high-dose radiation using radioprotectants (radiation treated), whereas the other group was frozen immediately without specific treatment (non-radiation treated). Both radiation-treated and non–radiation-treated DBM material from each group of hydrogen peroxide exposure times were implanted between L4 and L5 transverse processes of the rats forming eight test groups including eight animals in each. The remaining 16 rats were divided into two additional groups to form negative (only decortication, n=8) and positive (bone morphogenetic protein [BMP]-2, n=8) control groups. The rats were evaluated for fusion by radiographs (2, 4, and 8 weeks), manual palpation (8 weeks), and histological analysis after sacrificing. Comparison of fusion rate among all groups was made using these three evaluation methods. Results Increasing the time period of hydrogen peroxide (0, 1, 6, or 24 hours) exposure for preparation of DBM from bone allograft did not affect the fusion rates significantly (p<.05), although there was a trend toward decreasing fusion rates with longer exposure times. When the hydrogen peroxide washed DBM preparations were also radiation treated, the resulting fusion rates were again not significantly different (p<.05). Agreement among fusion detection methods was found to be high. Conclusions Hydrogen peroxide processing was not detrimental to fusion rates. The additional terminal sterilization technique with special gamma irradiation protocols (Clearant process) also did not decrease the fusion rates but could provide an additional margin of safety.