TissueDB/Materials/Foam, soft
License: CC0-1.0 by Robert Fotograf
Soft foam is lightweight, compressible foam — the kind found in mattresses, upholstery and packing padding, sponges, and craft-foam sheets — used in surgical simulation as a cheap stand-in for soft, compressible tissue layers (skin, subcutaneous fat, connective tissue, muscle) and, cut to shape, for organ bulk. PU foam is the polyurethane form of it. A sheet that blends ethylene-vinyl acetate with polyurethane is sold as Foam (EVA-PU blend) and cut into pads of differing density for layered tissue practice. Yellow foam is the dyed form used for the liver edge and other organ surfaces in laparoscopic trainers. It spans open-cell foams (foam sponge, polyurethane upholstery and packing foam), which are porous so castable materials soak in and bond to them,[1] and closed-cell foams (EVA craft-foam sheets, sold as "foam fabric"), which are smoother and cut cleanly into layers. "Firmness" is described by ILD (indentation load deflection) or plainly soft-to-extra-firm — an extra-firm mattress foam resists a scalpel more than a soft sponge, but all of it still deforms under the finger, so a foam mattress is soft foam, not rigid. Most soft foam is bought ready-made — sold as mattress and upholstery offcuts, kitchen and craft sponges, EVA craft-foam sheets ("foam fabric"), headliner foam, packing-foam blocks and EVA pool noodles — and some is cast from a two-part pour. Rigid polystyrene / packing "Styrofoam" is a different, non-deforming material and is not soft foam.
Tissues
| Tissue | Visual | Tactile | Simulator | Notes |
|---|---|---|---|---|
| Connective tissue (deep soft-tissue / chest-wall layer) | Suturing Simulator (Kumaresan), Chest Tube (Man-O-War), Multipurpose Thoracic (Carter) | As a synthetic foam sponge (4–5 mm), the deeper connective-tissue layer of a suturing pad — its open structure lets the impression material soak in and bond the layers (Suturing, Kumaresan).[1] As an extra-firm foam mattress (60 × 30 × 5 cm), the single undifferentiated chest-wall layer the learner incises, dissects and sutures (Chest Tube, Man-O-War; the source does not name the polymer). As ~6 mm headliner foam, the chest-wall soft-tissue cover (Multipurpose Thoracic, Carter; the paper's body text says headliner foam, its figure caption "thin felt"). | ||
| Connective tissue (subcutaneous fat, limb) | Synthetic Tourniquet (Souza Lima) | As 50 cm of upholstery foam filling a commercial mannequin leg — one undifferentiated fill that stands in for both the subcutaneous fat and the musculature, under an EVA-sheet skin; the source does not differentiate the two layers or give a foam density (Synthetic Tourniquet, Souza Lima).[2] | ||
| Skin (epidermis + dermis) | Z-Plasty Simulator, Lumbar Laminectomy (Bakhshi), Synthetic Tourniquet (Souza Lima), Chest Tube (Man-O-War) | As two glued craft-foam (EVA) "foam-fabric" sheets (12 × 12 cm) in contrasting colours for the dermis and epidermis, with elasticity like the web between thumb and index finger (Z-Plasty). As a book-fold foam block covered in rexine (a coated fabric) whose slit upper half is the incision site (Lumbar Laminectomy, Bakhshi). As a single 60 × 40 cm EVA sheet coating the exterior of a mannequin leg as the skin layer (Synthetic Tourniquet, Souza Lima).[2] As an extra-firm ("extra dur") foam mattress (60 × 30 × 5 cm), the layer that takes the learner's initial skin incision; the build has no separate skin layer, so the same foam is both the skin and the chest wall dissected beneath it (Chest Tube, Man-O-War; the source does not name the polymer). | ||
| Skin and subcutaneous tissue | Intra-abdominal Bleeding (Fernandes), Percutaneous Renal Access (Ewald) | As a thin sponge layer bonded to an EVA plate — one laminated 72 × 54 cm piece forming the anterior skin-and-subcutaneous wall (Intra-abdominal Bleeding, Fernandes).[3] As Premium Poly Foam (American Excelsior Company, Arlington TX) encasing the gelatin kidney block to mimic the overlying skin, fat and muscle (Percutaneous Renal Access, Ewald).[4] | ||
| Fascia | Z-Plasty Simulator | An additional glued foam-fabric layer (12 × 12 cm) representing the fascial plane beneath the skin sheets (Z-Plasty).[5] | ||
| Muscle | Laparoscopic Inguinal Hernia (Kurashima), Synthetic Tourniquet (Souza Lima) | Sponge layers in a five-layer abdominal-wall insert, each wrapped in white stretchy fabric to form the fascia; the source states five layers but does not say how many are muscle (Kurashima).[6] As 50 cm of upholstery foam filling a mannequin leg as the musculature — the same undifferentiated fill as the subcutaneous-fat row above (Synthetic Tourniquet, Souza Lima).[2] | ||
| Adipose tissue (subcutaneous) | Trocar Placement Simulator, Laparoscopic Inguinal Hernia (Kurashima) | As a ~15 × 15 cm sponge square (holes cut for pen-holder "ports") layered between the felt skin and the taped-felt fascia (Trocar Placement Simulator). As sponge for the subcutaneous adipose layer, thickness not stated in the source (Kurashima).[7][6] | ||
| Cartilage (tracheal rings) | Cricothyrotomy Simulator (White UW), Cricothyrotomy Simulator (D'Auria) | Compliant foam strips as the tracheal-ring cartilage; the source does not specify the foam grade, ring count, density, thickness or spacing (Cricothyrotomy, White UW). The D'Auria trainer is built on the same University of Washington substrate and uses the same compliant foam strips, which carry the conductive-foil contact sensors (Cricothyrotomy, D'Auria).[8] | ||
| Lung | Emergency Department Thoracotomy (Misra) | A soft packing-foam block (16 × 10 × 4 in) handcrafted into a lung shape as the substrate, wrapped in a layer of pink-coloured gauze, then coated with liquid plastisol (Bait Plastics LLC); about US$18 for the pair (Emergency Department Thoracotomy, Misra).[9] | ||
| Skin and subcutaneous tissue (wounded, debridement model) | UGHE Low-Cost Soft-Tissue Simulation Module | As a large sponge cut to represent wounded skin and tissue - the whole substrate of the wound-debridement model, with vinyl pieces set into the cuts as debris and red liquid latex painted on as blood (US$0.63 per model, Rwanda). A small thick sponge (US$0.50) is also the base of the abscess-drainage and nodule-excision models, where the source describes its role only as "the tissue beneath the abscess" and names no tissue for it. Documented limitation: air trapped in the sponge base introduces reverberation and shadowing artefacts that are not representative of live tissue, which the authors state potentially limits ultrasound realism and is a limitation of the model.[10] | ||
| (Structural — cushion layers, role not assigned in the source) | Orthoplastic Reconstruction Simulator | Two 45 × 10 cm sponge pieces, one laid on the wooden board beneath the pipe segments and one over the pipes and the fracture gap, glued at the edges if they lift. The build source describes only their size and placement and assigns them no tissue.[11] |
Troubleshooting
The following limits were recorded for closed-cell EVA craft foam and are kept at that scope; open-cell foam sponge behaves differently and is used as a suturing-pad layer above.
- Hemostasis training — EVA foam does not simulate vascular response or bleeding. Trainees cannot develop blood loss recognition skills.
- Thermal injury training — EVA foam melts under heat; do not use for electrosurgical training. Fire hazard; unrealistic tissue response.
- Suturing and knot-tying — EVA foam does not simulate tissue grip or needle resistance. Trainees develop incorrect suture tension calibration.
- Deep dissection and layer-specific anatomy — Does not differentiate muscle, peritoneum, or viscera. No layer recognition training.
Alternatives
| Alternative | Best For | Trade-offs |
|---|---|---|
| Silicone | Suturable, realistic texture | Higher cost; requires molding |
| Felt | Fascial "pop" sensation | Different tactile properties |
| Gelatin | Cutting fidelity, bleeding simulation | Requires refrigeration; limited shelf life |
References
- ↑ 1.0 1.1 Kumaresan R, Pendayala S, Srinivasan B, Kondreddy K. A simplified suturing model for preclinical training. Indian J Dent Res 2014;25(4):541–543. DOI 10.4103/0970-9290.142577. PMID 25307925.
- ↑ 2.0 2.1 2.2 Souza Lima D, Almeida YADS, Cid DMC, Cardoso LC, Braga CS, Regis FGL. Low-cost synthetic tourniquet training model. Rev Col Bras Cir 2019;46(6):e20192324. DOI 10.1590/0100-6991e-20192324. PMID 31967244.
- ↑ Fernandes CO, Rodrigues LR, Silva do Amaral MLBS, de Morais Rodrigues SJ, Marton-Filho MA. Low-cost simulator for intra-abdominal bleeding. Rev Col Bras Cir 2023;50:e20233512. DOI 10.1590/0100-6991e-20233512-en. PMID 37971114. PMC PMC10618030.
- ↑ Ewald JM, Cheng JW, Engelhart SM, Wilkinson MC, Hajiha M, Wagner H, Baldwin DD. A realistic, durable, and low-cost training model for percutaneous renal access using ballistic gelatin. Turk J Urol 2019;45(1):31–36. DOI 10.5152/tud.2018.43569. PMID 30668307.
- ↑ AmoSmile Physical Simulator. AmoSmile team, Appropedia.
- ↑ 6.0 6.1 Kurashima Y, Feldman LS, Al-Sabah S, Kaneva PA, Fried GM, Vassiliou MC. A tool for training and evaluation of laparoscopic inguinal hernia repair. Surg Innov 2011;18(2):171–175. DOI 10.1177/1553350610395949. PMID 21307013.
- ↑ ALL-SAFE Consortium. ALL-SAFE Trocar Placement Simulation Build Instructions. Pan-African Academy of Christian Surgeons, University of Michigan, Southern Illinois University, Soddo Christian Hospital, AIC Kijabe Hospital, Mbingo Baptist Hospital. Available at: PDF.
- ↑ D'Auria D, Persia F. "Automatic evaluation of medical doctors' performances while using a cricothyrotomy simulator." 2014 IEEE 15th International Conference on Information Reuse and Integration (IRI 2014), 13–15 August 2014, pp. 514–519. DOI 10.1109/IRI.2014.7051932.
- ↑ Misra A, Chapman A, Watson WD, Bach JA, Bonta MJ, Elliott JO, Dominguez EP. Use of low-cost task trainer for emergency department thoracotomy training in general surgery residency program. J Surg Educ 2024;81(1):134–144. DOI 10.1016/j.jsurg.2023.09.009. PMID 37926660.
- ↑ Wittenberg RE, Bryce-Alberti M, Shimelash NZ, Masimbi O, Kratky LE, Thompson AA, et al. Low-cost simulation models for soft-tissue procedures for medical student education in Rwanda. BMC Medical Education 2025;25(1):1271. DOI: 10.1186/s12909-025-07910-4. PMID 41034833. PMC PMC12487576. Licensed CC BY-NC-ND 4.0.
- ↑ Orthoplastic reconstruction/Physical Simulator — the physical simulator of the Orthoplastic Reconstruction training module, part of the Global Surgical Training Challenge, developed by the AmoSmile team; Appropedia, CC BY-SA 4.0.