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This page describes products and general use; it is not medical advice.
Short answer
Granufoam is a black polyurethane ether dressing engineered for negative pressure wound therapy (NPWT). Featuring an open-pore reticulated structure with pore diameters between 400 and 600 micrometers, it acts as a hydrophobic manifold that uniformly distributes sub-atmospheric pressure across the wound bed, draws exudate into an external canister, and stimulates granulation tissue formation via microstrain and macrostrain mechanics.
Definition and scope
Granufoam (distributed as V.A.C.® GranuFoam™ by Solventum, formerly 3M Health Care and Kinetic Concepts, Inc. / KCI) is an open-cell, reticulated polyurethane ether foam dressing designed specifically for negative pressure wound therapy systems. Unlike conventional absorbent dressings such as bordered silicone foam wound dressings that capture and store exudate internally, Granufoam operates strictly as an active fluid transport manifold and mechanical tissue interface under vacuum.
Under the FDA CDRH regulatory framework, Granufoam and associated NPWT systems are classified as Class II medical devices governed by 21 CFR § 878.4780 (Powered suction pump) under product code OMP. Premarket clearances include 510(k) notifications K133276 (covering Granufoam, Granufoam Thin, Granufoam Round, and WhiteFoam dressings) and K212320 (covering Dermatac™ Drape and V.A.C. Granufoam dressings featuring SensaT.R.A.C.™ technology).
According to device registration records in the openFDA device classification database and the Global Unique Device Identification (GUDID) system (Primary Device Identifier: 00849554009066), Granufoam dressings are designated as prescription-only (Rx Only), single-use sterile devices. They are sterilized via gamma irradiation, verified as MR Safe, and labeled as not made with natural rubber latex to prevent hypersensitivity reactions.
The clinical scope encompasses complex wound management across acute surgical care, trauma units, burn centers, outpatient wound clinics, and subacute facilities. Cleared indications include chronic, acute, traumatic, subacute, and dehisced surgical wounds; partial-thickness burns; flaps and meshed grafts; and stage 3 and 4 pressure injuries, diabetic foot ulcers, and venous ulcers. In clinical research evaluating wound healing kinetics, Granufoam serves as the benchmark interface against which novel wound matrices and cellular products are compared.
How it works or how it is used in practice
Granufoam functions through a dual biomechanical and fluid-dynamic mechanism when connected to a calibrated negative pressure suction unit. The reticulated open-cell network features pore diameters ranging precisely between 400 and 600 micrometers (μm). Pores below 400 μm provide insufficient tissue micro-deformation, whereas pores exceeding 600 μm can cause excessive tissue ingrowth, leading to painful dressing removal and disruption of capillary buds.
When negative pressure is applied—typically at a nominal baseline of -125 mmHg continuous or intermittent suction—the foam undergoes macrostrain and microstrain, two distinct mechanical phenomena identified in foundational evaluations (such as research published by Saxena et al. in Plastic and Reconstructive Surgery):
- Macrostrain (Physical Contraction): Under negative pressure, the open pores collapse inward, drawing wound margins together, eliminating dead space in cavities, and stabilizing surrounding tissue margins.
- Microstrain (Cellular Deformation): At the interface where polyurethane struts contact the wound bed, open pores exert localized tension on wound cells, creating 5% to 20% microscopic cellular strain. This mechanical stretch activates intracellular mechanotransduction, increasing vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) expression, accelerating cellular mitosis, and promoting granulation tissue formation.
In addition to biomechanical stimulation, Granufoam acts as a high-capacity fluid conduit. Because polyurethane ether is hydrophobic (water-repelling), the foam struts do not absorb water. Instead, wound exudate, cellular debris, matrix metalloproteinases (MMPs), and bacterial bioburden are rapidly drawn through open pores and transported through the SensaT.R.A.C. tubing pad into an external collection canister. This rapid clearance reduces local tissue edema, decreases interstitial hydrostatic pressure, restores capillary perfusion, and lowers bioburden.
In clinical practice, wound bed preparation is essential prior to dressing placement. Wounds undergo debridement to remove necrotic eschar, followed by cleansing with sterile saline or surfactant solutions such as Puracyn hypochlorous acid cleansers. Clinicians cut the foam to fit the wound cavity; manufacturer instructions for use (IFU) strictly require that foam never be cut directly over the open wound to prevent loose polyurethane particles from falling into the bed.
The foam is placed loosely into the cavity without over-packing, sealed with an adhesive drape extending 3 to 5 cm onto intact periwound skin, and connected to the vacuum pump. Clinicians confirm the foam compresses completely into a firm consistency, verifying an airtight seal. Operating pressure typically ranges from -75 mmHg to -150 mmHg, with -125 mmHg representing the validated default setting. Dressings are routinely replaced every 48 to 72 hours under sterile or clean technique.
Types or related concepts
Within negative pressure wound therapy protocols, multiple specialized foam substrates and interface materials are employed. Selecting the correct foam variant is critical for clinical efficacy, patient comfort, and tissue safety. The following table provides a sourced comparison of Granufoam and related negative-pressure wound interfaces based on manufacturer specifications, FDA clearances, and published clinical guidelines.
| Dressing Type | Base Material & Pore Architecture | Nominal Operating Pressure | Primary Clinical Indication | Key Distinguishing Features |
|---|---|---|---|---|
| Standard V.A.C. GranuFoam | Reticulated polyurethane ether; open pores (400–600 μm); hydrophobic | -125 mmHg (range: -75 to -150 mmHg) | Acute, chronic, traumatic, and dehisced wounds; pressure and diabetic ulcers | Maximum granulation stimulation; rapid fluid evacuation; flexible and easily contoured. |
| V.A.C. GranuFoam Silver | Polyurethane ether foam microbonded with elemental metallic silver; open pores (400–600 μm) | -125 mmHg (range: -75 to -150 mmHg) | Critically colonized or infected wounds; high bioburden management | Continuous ionic silver release upon contact with wound exudate; broad-spectrum antimicrobial barrier. |
| V.A.C. WhiteFoam | Polyvinyl alcohol (PVA); high-density micro-pores; hydrophilic | -125 to -175 mmHg | Exposed bone, tendon, nerves, or tunneling; split-thickness skin grafts | Denser structure; non-adherent interface prevents tissue ingrowth; requires pre-moistening with sterile saline. |
| V.A.C. Veraflo Cleaniseal Foam | Reticulated polyurethane foam with through-holes; hydrophobic | -125 mmHg with dwell cycles | Negative pressure wound therapy with instillation and dwell (NPWTi-d) | Engineered through-hole architecture allows automated delivery and distribution of topical instillation solutions. |
| Granufoam Thin / Round | Reticulated polyurethane ether; reduced profile or circular pre-cut | -125 mmHg (range: -75 to -125 mmHg) | Shallow wounds, neuropathic plantar ulcers, circular excision defects | Low-profile geometry prevents excess bulk and reduces pressure on periwound margins in contoured anatomical sites. |
Understanding the distinction between standard Granufoam and WhiteFoam is a critical clinical decision point. While Granufoam aggressively stimulates granulation tissue through its 400 to 600 μm open pores, rapid tissue ingrowth can cause the foam to adhere to exposed collagenous structures or sensitive tissues. When negative pressure is applied directly over exposed tendons, ligaments, periosteum, or neural structures, Granufoam can adhere to bone or sheath, causing trauma and pain upon removal.
In contrast, V.A.C. WhiteFoam is constructed from hydrophilic polyvinyl alcohol (PVA) with higher density and smaller pore diameters. It resists tissue ingrowth, making it the preferred contact layer over exposed bone, tendon, or graft donor sites. In composite wounds, clinicians frequently utilize a hybrid technique: a layer of WhiteFoam or a non-adherent silver barrier like Silverlon antimicrobial contact dressings is placed directly over delicate structures, while Granufoam is placed on top to bridge dead space, facilitate vacuum transmission, and evacuate exudate.
Where it matters for labs, clinics or supply decisions
Managing Granufoam inventory and clinical utilization requires alignment across procurement, materials management, nursing staff, and billing compliance teams. Because NPWT is a specialized therapy subject to regulatory oversight and payer auditing, health systems must establish standardized operational workflows.
CMS HCPCS Level II Coding and Reimbursement Rules
In the United States, outpatient and home-health negative pressure wound therapy is governed by the Centers for Medicare & Medicaid Services (CMS) under Medicare Part B Durable Medical Equipment (DME) Local Coverage Determination (LCD) L33821 and Policy Article A52499. The relevant Healthcare Common Procedure Coding System (HCPCS) codes include:
- HCPCS A6550: Wound care set, for negative pressure wound therapy electrical pump, includes all supplies and accessories. Covers the complete dressing kit: Granufoam dressing, polyurethane drape, and SensaT.R.A.C. tubing pad with connector.
- HCPCS A7000: Canister, disposable, used with pump, replacement only. Covers the exudate collection canister (standard 300 mL, 500 mL, or 1000 mL capacities).
- HCPCS E2402: Negative pressure wound therapy electrical pump, stationary or portable. Covers rental of the powered vacuum pump unit.
Medicare DME MAC carriers enforce strict monthly utilization caps. Under LCD L33821, reimbursement for HCPCS code A6550 is capped at a maximum of 15 dressing kits per wound per month, reflecting an expected dressing change frequency of every 48 hours (approximately 3 dressing changes per week). Billing beyond 15 kits per month triggers claim suspension and requires documented clinical justification of medical necessity. Similarly, HCPCS code A7000 is capped at 10 canisters per month. Higher canister utilization requires documentation proving exudate exceeds 90 mL per day, utilizing large-capacity canisters (e.g., 1000 mL).
Documentation Mandates and Clinical Research Governance
Prior to claim submission, providers must execute a Standard Written Order (SWO) signed by the treating licensed practitioner. Clinical staff must document objective wound measurements—length, width, and depth in centimeters, undermining or tunneling, exudate volume, and percentage of granulation tissue—at least once every 30 days. Under CMS guidelines, therapy must demonstrate continuous progress toward healing; static wound dimensions over four consecutive weeks require formal clinical re-evaluation.
In clinical trials and academic laboratories evaluating tissue engineering scaffolds, bioprinted constructs, or topical agents, Granufoam is frequently utilized in controlled animal models and human clinical studies. Protocols must track lot numbers, sterilization dates, pump calibration records, and negative pressure dynamics using automated data acquisition to isolate experimental variables from baseline NPWT mechanical stimulation.
Clinical Supply Chain and Risk Mitigation Protocols
Hospital central supply and clinic procurement managers must enforce three operational checkpoints:
- Sterile Barrier and Shelf-Life Inspection: Granufoam kits are sterile single-use devices with manufacturer-specified shelf lives (typically 3 years). Supply rooms must enforce first-in, first-out (FIFO) rotation and verify packaging integrity prior to dispensing.
- Kit Sizing Standardization: Facilities should maintain balanced inventory across Small, Medium, and Large kits. Over-relying on Large kits causes substantial material waste, whereas using undersized kits necessitates combining multiple pieces, increasing clinical complexity.
- Mandatory Piece-Count Protocol (Foreign Body Prevention): Retained foam inside a wound cavity represents a severe complication causing infection and surgical re-exploration. Clinical protocols must mandate that the exact number of foam pieces placed into the wound is documented directly on the exterior drape and in the electronic health record (EHR). Clinicians must count and verify complete piece removal before applying new foam.
Common misunderstandings
Despite the widespread adoption of negative pressure wound therapy, several persistent misconceptions surround Granufoam in clinical and supply chain operations:
Misconception 1: Granufoam functions as an absorbent dressing
A frequent error is assuming Granufoam acts similarly to hydrophilic foam dressings that absorb and hold exudate within the dressing structure. Granufoam is hydrophobic; its ether-based polyurethane polymer repels moisture. It does not retain or store fluid. Instead, it serves solely as an open conduit that channels exudate away from tissue under vacuum into the collection canister. Attempting to use Granufoam as a passive secondary dressing without an active vacuum pump results in exudate pooling, rapid maceration, and dressing failure.
Misconception 2: Granufoam can be placed directly over vital vascular structures
Placing Granufoam in direct contact with exposed blood vessels, vascular graft anastomoses, organs, or nerves is an absolute contraindication established by the FDA and manufacturer safety warnings. Because Granufoam exerts microstrain and stimulates tissue ingrowth into its 400 to 600 μm pores, direct placement over unprotected vessels can lead to erosion and severe hemorrhage upon dressing removal. Clinicians must interpose an appropriate protective barrier—such as WhiteFoam or non-adherent protective sheets—prior to foam placement.
Misconception 3: Standard Granufoam can be used in instillation therapy systems
Some facilities attempt to reduce supply costs by utilizing standard Granufoam kits rather than dedicated through-hole instillation foams (e.g., Veraflo Cleaniseal). This practice is clinically flawed. Standard Granufoam lacks through-holes; instillation fluid follows the path of least resistance toward the suction port rather than distributing evenly across the wound bed, resulting in incomplete irrigation and compromised bacterial clearance.
Misconception 4: Foam can be trimmed directly above the open wound
Trimming Granufoam while holding it directly over the wound cavity violates manufacturer instructions for use. Trimming reticulated foam generates microscopic and macroscopic polyurethane debris that can fall into tissue crevices, acting as non-absorbable foreign bodies that provoke chronic inflammation. Foam must always be measured and trimmed away from the wound bed.
Misconception 5: NPWT dressings can remain in place indefinitely during pump downtime
Manufacturer clinical guidelines specify that foam dressings must never remain in place without active negative pressure for more than two hours. Without active suction, collapsed foam ceases to evacuate exudate, creating an occluded fluid reservoir that fosters bacterial proliferation and tissue maceration. If therapy is interrupted for more than two hours, the dressing must be removed and replaced with a conventional sterile dressing until NPWT can be resumed.
Frequently asked questions
What is Granufoam made of, and why is its pore size important?
Granufoam is composed of reticulated, open-cell polyurethane ether with pore diameters engineered specifically between 400 and 600 micrometers (μm). This diameter optimizes the balance between mechanical tissue stimulation and clinical safety: it provides sufficient microstrain (5% to 20% cellular deformation) to accelerate cell mitosis and granulation tissue formation while preventing excessive tissue embedding associated with larger pores.
What is the difference between Granufoam and Whitefoam?
Granufoam is a black, hydrophobic polyurethane ether foam with large open pores (400–600 μm) designed for aggressive granulation and rapid exudate transport at standard -125 mmHg pressure. WhiteFoam is a white, hydrophilic polyvinyl alcohol (PVA) foam with dense, fine pores and higher tensile strength. WhiteFoam resists tissue ingrowth, making it the preferred choice for placement over exposed bone, tendon, nerves, or skin grafts, operating at -125 to -175 mmHg.
What are the absolute contraindications for using Granufoam in NPWT?
According to FDA regulations and manufacturer instructions for use, Granufoam is strictly contraindicated in the presence of: untreated osteomyelitis; necrotic tissue with dry eschar; active malignancy within the wound bed; non-enteric and unexplored fistulas; and direct placement over exposed blood vessels, anastomotic sites, organs, or nerves without a protective non-adherent barrier.
What HCPCS codes are used for billing Granufoam dressings and supplies?
Under CMS Medicare Part B DME guidelines, Granufoam dressing kits (including foam, adhesive drape, and tubing pad) are billed under HCPCS code A6550 (capped at 15 kits per wound per month). Replacement fluid canisters are billed under HCPCS code A7000 (capped at 10 canisters per month unless daily drainage exceeds 90 mL). The powered suction pump is billed separately under HCPCS code E2402.
How often should Granufoam dressings be changed in clinical practice?
Standard Granufoam dressings must be changed every 48 to 72 hours, or at least three times per week. In infected wounds or wounds with heavy drainage, daily dressing changes may be clinically indicated. Dressings must never remain sealed without active negative pressure for more than two hours.
What negative pressure settings are typically prescribed with Granufoam?
The standard, clinically validated target pressure for Granufoam is -125 mmHg continuous suction. Depending on patient comfort, anatomical location, and clinical goals, physicians may prescribe pressures ranging from -75 mmHg to -150 mmHg. Continuous therapy is typically used for the initial 24 to 48 hours, with intermittent therapy considered subsequently based on patient tolerance.
Sources
- U.S. Food and Drug Administration (FDA): 21 CFR § 878.4780, Powered Suction Pump (Product Code: OMP, Class II Medical Device). Accessed 2026-11-12. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=878.4780
- U.S. Food and Drug Administration (FDA): 510(k) Premarket Notification K133276 (V.A.C. Granufoam Dressing, Granufoam Thin, Granufoam Round, WhiteFoam). Cleared 2013-11-19. Accessed 2026-11-12. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K133276
- U.S. Food and Drug Administration (FDA): AccessGUDID / openFDA UDI Database (V.A.C. Granufoam Dressing, Primary DI: 00849554009066). Accessed 2026-11-12. https://api.fda.gov/device/udi.json?search=brand_name:granufoam
- Centers for Medicare & Medicaid Services (CMS): Local Coverage Determination (LCD) L33821: Negative Pressure Wound Therapy Pumps and Supplies (HCPCS A6550, A7000, E2402). Accessed 2026-11-12. https://www.cms.gov/medicare-coverage-database/view/lcd.aspx?lcdid=33821
- Solventum / 3M Health Care / KCI: V.A.C.® Therapy Clinical Guidelines and GranuFoam Instructions for Use (IFU). Accessed 2026-11-12. https://www.solventum.com
- National Center for Biotechnology Information (NCBI) / PubMed: Saxena, V., et al. (2004). “Vacuum-Assisted Closure: Microdeformations of Wounds and Cell Proliferation.” Plastic and Reconstructive Surgery, 114(5): 1086-1096. PMID: 15454684; PMCID: PMC2769062. Accessed 2026-11-12. https://pubmed.ncbi.nlm.nih.gov/15454684/
