DEMINERALIZED BONE MATRIX (DBM)

biological scaffold | growth factor delivery | bone induction

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peer-reviewed sources only. all studies cited.

[1] Wildemann B et al. (2020) DBM in Bone Repair: History and Use

[2] Aghdasi B et al. (2013) DBM for Spinal Fusion: Evidence Review

[3] Brouwer RJ et al. (2017) DBM in Trauma and Orthopaedics: Systematic Review

[4] Eastlack RK et al. (2023) DBM and Fibers in Spinal Fusion

[5] Srivastava A et al. (2024) Spine Biologics: DBM Systematic Review 2014-2024

[6] Schwartz Z et al. (1998) Donor Age and Gender Effects on DBM Osteoinductivity

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CONTENTS

01 what is DBM

02 how it is processed

03 mechanism of action

04 growth factors: each one

05 clinical evidence

06 the variability problem

07 DBM vs other grafting options

08 commercial products

09 safety and risks

10 next generation DBM

11 verdict

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DEMINERALIZED BONE MATRIX

Allograft bone from a cadaveric donor with its mineral component

dissolved out by acid. What remains is the organic collagen matrix

plus the bioactive proteins that were embedded inside the bone.

Those proteins are growth factors. They recruit the patient's own

stem cells and direct them to differentiate into osteoblasts,

which then produce new bone at the implant site.

This is what separates DBM from synthetic substitutes like

hydroxyapatite or tricalcium phosphate. Synthetics are passive

scaffolds. DBM carries biological instructions.

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First described 1965, Marshall Urist (UCLA)

Key finding subcutaneous DBM in rabbits caused de novo bone formation

Clinical use since early 1970s

Global market share approximately 20% of all bone grafting procedures

US procedures/year approximately 108,000

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Available forms:

putty / paste / gel / flexible sheets / granules / powder

THE PROCESSING PIPELINE

Every step either preserves or degrades the biological activity

that makes DBM useful. This is also the source of the variability

problem covered in section 06.

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STEP 1 donor procurement

Cortical long bones (femur, tibia, fibula) from screened cadaveric donors.

Donors tested for HIV, hepatitis B/C, syphilis, HTLV.

Regulated as HCT/P under FDA 21 CFR Part 1271.

No pre-market clinical efficacy requirement for the final product.

STEP 2 cleaning and defatting

Soft tissue and marrow removed. Lipids extracted with organic solvents

or detergents. Strips most cellular material (HLA antigens), reducing

immunogenicity. Protocol varies by tissue bank. No industry standard.

STEP 3 demineralization

HCl at 0.5-0.6 N dissolves calcium hydroxyapatite.

The mineral normally traps growth factors inside the bone matrix.

Removing it exposes those factors for release in vivo.

Target residual calcium content: below 8% of dry weight.

Variables that determine product quality:

acid concentration / acid-to-bone ratio / temperature

agitation / contact time / particle size / residual calcium

STEP 4 sterilization

gamma irradiation effective sterility / denatures BMP and TGF-beta

electron beam (wet) reduces osteoinductivity by approximately 22%

ethylene oxide lower protein damage / sterility concerns at low dose

peracetic acid best balance of sterility and growth factor preservation

STEP 5 carrier addition

Raw DBM powder has no handling properties. Carriers added:

glycerol / sodium hyaluronate / gelatin / calcium sulfate

The carrier dilutes the active DBM content.

Carrier-to-DBM ratio is not required to be disclosed on the label.

TWO MECHANISMS

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OSTEOINDUCTION

The active biological mechanism. DBM releases growth factors into

the wound environment. Those factors recruit mesenchymal stem cells

from host periosteum, endosteum, and bone marrow. The same signals

drive MSC differentiation into osteoblasts. New bone forms in tissue

that was not previously bone. This is what synthetics cannot do.

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OSTEOCONDUCTION

The passive structural mechanism. The collagen matrix provides a

3D scaffold that bone-forming cells migrate along, attach to, and

use as a template for new bone matrix deposition.

DBM is weakly osteoconductive relative to HA scaffolds. Its collagen

matrix degrades quickly, which limits structural support but allows

complete replacement by host bone without permanent foreign material.

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SEQUENCE AFTER IMPLANTATION

1 DBM placed at defect site

2 BMP-2/7 and PDGF diffuse into surrounding tissue

3 MSCs recruited from host periosteum/endosteum/marrow

4 MSCs differentiate into osteoblasts under BMP/TGF-beta signals

5 osteoblasts migrate along collagen scaffold

6 osteoblasts synthesise osteoid (collagen I matrix)

7 FGF drives angiogenesis to sustain the process with blood supply

8 mineralisation of osteoid via calcium phosphate deposition

9 scaffold remodels and is replaced by host lamellar bone

GROWTH FACTOR PORTFOLIO

DBM releases a portfolio of proteins that work across different

phases of bone formation. Not a single molecule. A system.

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BMP-2 Bone Morphogenetic Protein 2

Primary driver. Recruits MSCs from surrounding tissue and drives

their commitment to the osteoblast lineage. Member of the TGF-beta

superfamily. Same protein used at supraphysiological doses in rhBMP-2

products (Infuse). In DBM it is present at natural physiological

concentrations. Content varies by donor age, processing, and product.

BMP-7 Bone Morphogenetic Protein 7 / OP-1

Synergises with BMP-2. Independently stimulates bone formation.

Also known as Osteogenic Protein-1. Amplifies the BMP-2 osteoinductive

signal and supports later-stage mineralisation.

TGF-beta1 Transforming Growth Factor beta-1

Confirmed present and functionally active in processed DBM via ELISA.

A 2021 study (OraGRAFT products) confirmed TGF-beta1 survives standard

demineralization, virus inactivation, and sterilization steps.

Drives osteoblast proliferation and matrix synthesis. Modulates immune

environment around the implant, reducing inflammatory scaffold degradation.

IGF-1 and IGF-2 Insulin-like Growth Factors

Promote osteoblast survival, proliferation, and bone matrix synthesis.

Synergistic with BMPs. IGF-1 has a well-characterised role in coupling

bone resorption to formation during normal remodelling cycles.

FGF Fibroblast Growth Factor

Drives angiogenesis at the graft site. New blood vessel formation

is required to sustain bone formation beyond the initial phase.

Without vascular supply, osteoblast activity stalls due to hypoxia

regardless of how many cells have been recruited.

PDGF Platelet-Derived Growth Factor

Recruits additional MSCs and stimulates early cellular proliferation.

Accelerates initial colonisation of the scaffold in the first days

after implantation.

Osteocalcin and Osteopontin

Non-collagenous bone matrix proteins. Regulate mineralisation of

newly formed osteoid and mediate osteoblast adhesion to the scaffold.

CLINICAL RESULTS BY APPLICATION

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CERVICAL SPINE FUSION (strongest evidence)

Kim et al 100% fusion rate, Grafton DBM alone in ACDF

Roh et al 97% fusion, Grafton DBM in LLIF

An et al allograft plus DBM equivalent to autograft in ACDF

prospective multicenter study

Gatam et al DBM plus HA: 76.5% fusion vs 77.8% autograft at 1 year

3 of 5 cervical spine studies reported 100% fusion.

All reported noninferiority vs autograft.

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LUMBAR SPINE FUSION (variable evidence)

Cammisa et al Grafton gel equivalent to autograft at 2 years

prospective controlled, side-by-side in same patient

Lee et al 73% fusion with Grafton alone in OLIF

Hyun et al RCT DBM gel vs DBM gel plus rhBMP-2

no significant difference in fusion at 11 months

Ouyang et al DBM plus concentrated bone marrow aspirate

80 patients, successful fusion, low complications

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ADULT SPINAL DEFORMITY

Bari et al (2022) demineralized cortical fibers associated with reduced

pseudarthrosis after pedicle subtraction osteotomy

Heegaard et al (2023) low pseudarthrosis in deformity surgery without 3-col osteotomy

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FRACTURE REPAIR

Geesink et al 5 of 6 critical fibular defects treated with DBM alone

first human confirmation of Urist's 1965 rabbit data

Standard threshold defects exceeding 2cm require intervention beyond host repair

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CRANIOFACIAL (2024)

Helsinki University Hospital, 138 patients, 2014-2022

DBX vs autogenous bone graft in Le Fort I osteotomies

orofacial clefts and craniofacial malformations

comparable complications and reoperation rates between groups

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SYSTEMATIC REVIEW 2024

Srivastava et al, 10 years of spinal fusion DBM data

conclusion: high fusion rates as graft extender or enhancer

consistent finding: DBM standalone less reliable than as component of strategy

THE VARIABILITY PROBLEM

10 to 15 percent of commercial DBM preparations have no meaningful

osteoinductive activity. There is no way to tell from the packaging.

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SOURCE 1 DONOR BIOLOGY

Younger donors yield DBM with higher BMP content and greater

osteoinductive capacity. Schwartz et al (1998): statistically significant

linear decline in osteoinductivity with increasing donor age in males.

In females the relationship is less consistent.

Optimal donor window: approximately 45-55 years (Alaribe et al 2016).

Neither age nor gender is screened for by most tissue banks.

SOURCE 2 DEMINERALIZATION VARIABLES

incomplete demineralization: growth factors remain trapped in residual mineral

over-demineralization: collagen architecture and protein content damaged

particle size: smaller particles produce more bone per unit area (Glowacki et al)

no industry-wide particle size standard exists

SOURCE 3 STERILIZATION DAMAGE

gamma irradiation denatures BMP and TGF-beta directly

e-beam in wet state reduces osteoinductivity by approximately 22% (Qiu et al)

sterilization protocol is not disclosed on the product label

SOURCE 4 CARRIER DILUTION

carrier-to-DBM ratio is not standardised and not required to be disclosed

a product that is 30% DBM and 70% glycerol delivers far less biological

signal than one that is 70% DBM. indistinguishable at point of purchase.

SOURCE 5 REGULATORY GAP

DBM regulated under FDA Section 361 as minimally manipulated human tissue

no pre-market efficacy data required

no standardised osteoinductivity testing requirement

no comparative performance requirement before reaching surgeons

17 different commercial DBM products on the US market.

Performance varies enormously. Most comparative data is manufacturer-funded.

BONE GRAFTING OPTIONS COMPARED

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AUTOGRAFT (iliac crest bone graft)

mechanism osteoinduction + osteoconduction + osteogenesis (live cells)

evidence gold standard. most reliable option.

advantage all three bone-forming mechanisms. no immune response. no disease risk

disadvantage donor site morbidity. limited volume. extra surgical time and blood loss

verdict S-TIER biologically. limited by harvest cost

FROZEN / FREEZE-DRIED ALLOGRAFT

mechanism osteoconduction only (live cells and proteins destroyed by processing)

evidence extensive use. well-characterised.

advantage abundant supply. structural support. predictable resorption

disadvantage no osteoinduction. entirely dependent on host biology

verdict A-TIER structural scaffold / B-TIER biological signal

DBM as graft extender

mechanism osteoinduction + osteoconduction (no live cells)

evidence high fusion rates as extender. variable as standalone.

advantage retains natural growth factor portfolio. no harvest morbidity

disadvantage batch variability. 10-15% batches not osteoinductive. regulatory gap

verdict A-TIER as extender / B-TIER as standalone

DBM + BONE MARROW ASPIRATE

mechanism DBM osteoinduction + BMA live MSCs + BMA growth factors

evidence 80-patient cohort: successful fusion, low complications (Ouyang et al).

advantage addresses the missing live cell component of DBM alone. synergistic

disadvantage BMA harvest adds a procedure step (less morbid than ICBG)

verdict A+ TIER practical clinical standard

rhBMP-2 (Infuse / Medtronic)

mechanism supraphysiological BMP-2 dose. powerful osteoinduction.

evidence strong RCT data in lumbar fusion and tibial nonunion.

advantage consistent potent effect. no donor variability

disadvantage ectopic bone. osteolysis. retrograde ejaculation in ALIF. $5-8k per kit. cancer signal

verdict S-TIER efficacy. risk profile requires careful indication selection

SYNTHETIC SUBSTITUTES (HA / TCP / CaSO4)

mechanism osteoconduction only. no biological signalling.

evidence adequate for small contained defects. inferior for large voids.

advantage unlimited supply. consistent. no disease risk. cheap

disadvantage zero osteoinduction. relies entirely on host osteoblasts arriving independently

verdict B-TIER scaffold. best for contained small defects with competent host biology

17 PRODUCTS ON THE US MARKET. KEY ONES:

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GRAFTON (Osteotech / Medtronic)

most studied DBM in the literature. the reference product.

Gel, putty, flex, crunch. Glycerol carrier. Most comparative data references

Grafton. 100% ACDF fusion rates in multiple series.

DBX (MTF / Synthes)

sodium hyaluronate carrier. widely used in craniofacial.

Putty and mix formulations. Used in the 2024 Helsinki craniofacial study.

ALLOMATRIX (Wright Medical)

DBM plus calcium sulfate. dual mechanism.

Adds osteoconductive component to osteoinductive DBM. Calcium sulfate

resorbs predictably, creating local porosity. Enhanced osteogenic

differentiation vs native cancellous bone alone in vitro.

ACCELL EVO3 (Integra)

high DBM content. minimised carrier dilution.

Competitive with Grafton in rat posterolateral fusion models.

OraGRAFT (LifeNet Health)

dental and oral surgery specific. best growth factor preservation data.

Confirmed to retain functionally active TGF-beta1 through all standard

processing steps via ELISA quantification (2021 study).

NOTE:

Do not apply Grafton efficacy data to a different product.

Each product has its own processing protocol and performance profile.

SAFETY PROFILE

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DISEASE TRANSMISSION

All donors screened per FDA and AATB standards for HIV, hepatitis

B/C, syphilis, HTLV. Demineralization has partial pathogen inactivation

effect. Additional sterilization reduces residual risk further.

Estimated HIV transmission risk from processed allograft:

approximately 1 in 1,670,000

No documented HIV transmission from commercially processed DBM

meeting current standards has been reported.

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IMMUNE RESPONSE

Demineralization removes most HLA antigen-bearing cellular components.

Residual type I collagen is poorly immunogenic (conserved across individuals).

No HLA matching required. No immunosuppression required.

Clinically significant rejection is rare and self-limiting when it occurs.

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PRION RISK (CJD)

Theoretical. Standard processing does not fully inactivate prions.

No documented case of CJD transmission from processed bone allograft.

Donor screening excludes individuals with known neurological disease.

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GRAFT FAILURE AND PSEUDARTHROSIS

The primary clinical risk is non-union, not toxicity.

A DBM batch with low osteoinductivity in a high-demand fusion

environment will result in fibrous non-union rather than bone bridge.

Failed fusion means revision surgery.

This is why the variability problem is a safety issue, not only efficacy.

ACTIVE RESEARCH DIRECTIONS

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MAGNETIC FIELD AUGMENTATION (2024)

Human DBM in critically sized rat cranial defects exposed to 1 Tesla

external magnetic field showed superior bone formation vs DBM alone.

Mechanism: piezoelectric properties of bone collagen generate electrical

signals under magnetic stimulation that activate osteoblast differentiation.

Journal of Materials Chemistry B (2024). Pre-clinical.

NANOPARTICLE SFRP-1 SILENCING PLUS DBM

Nanoparticle delivery of antisense oligonucleotides silences SFRP-1

gene locally. Combined with DBM scaffolding, activates Wnt/beta-catenin

at the graft site to amplify the response to DBM-released BMPs.

Connects WAY-316606 mechanism directly to DBM biology.

Springer Nature (2022). Pre-clinical.

STEM CELL LOADED DBM

DBM scaffolds pre-seeded with MSCs before implantation address the

absent osteogenesis component. Pig model (2014): DBM plus BMP-2 and

TGF-beta3 transfected BMSCs showed complete full-thickness cartilage repair.

Regulatory and manufacturing complexity limits near-term translation.

PROCESSING STANDARDISATION

Honsawek et al: osteoinductive potential increases with decreased

mineralisation (mouse model). Glowacki et al: particle size effect

confirmed (rat model). Both cited in ongoing regulatory push for

industry-wide processing standards. Progress is slow.

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WHAT DBM IS

Processed cadaveric bone retaining the growth factor content of native

bone after acid mineral extraction. Actively recruits and differentiates

bone-forming cells. Provides a collagen scaffold. Provides no live cells.

60 years of clinical history.

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STRENGTHS

graft extender alongside autograft in spinal fusion

bone void filling in fracture repair

cervical spine fusion (strongest standalone evidence)

no donor site morbidity vs autograft

combined with bone marrow aspirate addresses missing cell component

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LIMITATIONS

unreliable as standalone graft in high-demand biological environments

cannot replace autograft where live cells determine outcome

10-15% of batches have no meaningful osteoinductive activity

batch variability structurally unsolved due to regulatory gap

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A-TIER as graft extender

B-TIER as standalone graft

Proven biology. Real clinical utility. Meaningful limitations.

Best used as part of a strategy, not as the whole strategy.

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educational reference. all information from peer-reviewed literature.

consult an orthopaedic surgeon for clinical decisions.

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