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A low-resource, replicable, and high fidelity hip model for ultrasound-guided nerve blocks

Julia Lerner, MD, MA, CMI, FAMI

Regional anesthesia in the ER

Why it matters

• Hip fracture pain is a top reason for ED visits in older adults
• Regional anesthesia reduces opioid doses and delirium
• Training opportunities are limited

Designed and sculpted by a board certified medical illustrator and emergency physician

Focused on preventing need for opioids and drug related delirium

Reproducible with 3D printing and silicone casting workflow

Reheatable and self-healing after needle passes

The educational & clinical need

  • Hip fractures are common and painful

  • Blocks reduce opioids and delirium

  • Training opportunities are scarce

  • Regional anesthesia is becoming more popular in ERs as doctors are graduating with more ultrasound experience

The training gap addressed

​Learners struggle with:

  • Deep, unfamiliar sonoanatomy

  • Needle visualization & guidance

  • Limited opportunities for safe repetition

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Existing options are:

  • High-cost commercial simulators

  • Cadavers with limited reusability

  • Opportunistic learning on real patients

What the model includes

The model is a 3D silicone box, in which hypoechoic ballistics gel is poured to represent soft tissue structures. 3D printed PLA bone remains embedded in the silicone, hyperechoic under ultrasound. This can be removed so silicone and ballistic gel can be reheated.

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Molds

3D printed internal anatomy, removed after silicone pouring

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Bone

Hyperechoic 3D printed material, removable for reheating

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Fascia

Silicone container representing connective tissue and interstitial space under ultrasound

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Muscle

Homemade ballistics gel, poured into the silicone "fascia"

How it was built

Each design decision maps to a specific educational challenge.

This went through multiple iterations to balance ultrasound fidelity, durability, and cost.

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Research & design

I started with pencil on paper, clarifying the anatomy included and how the parts fit together, with emphasis on cross-sectional anatomy

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Digital modeling & sculpting

Anatomy was digitally modeled and sculpted in Cinema 4D and then simplified for didactic clarity and model-making. Bone is derived from DICOM data.

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Mold creation

Sculpted meshes were combined into molds with soft tissues designated as negative space in the final cast model.

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3D Printing

Models were printed in PLA or ABS on a Bambulabs P1S.

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Casting

Silicone and additives to improve appearance under ultrasound were mixed, degassed in a vacuum chamber, and poured into the assembled mold.

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Ballistics gel

Homemade ballistics gel is poured into the silicone container with the "bone" removed. This can be reheated to heal the material.

Blocks you can train here

Demonstrated below on live human anatomy

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These four common hip blocks can be practiced on the model, helping learners visualize sonoanatomy and needle trajectory.

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These blocks anesthetize a variety of motor and sensory distributions in the lower extremity. Depending on the medication injected, they can achieve pain relief for hours to several days.

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Pericapsular nerve group (PENG)

  • Excellent analgesia without motor blockade

  • Deep anatomy which learners often struggle to visualize

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Fascia Iliaca

  • Go-to low risk fascial plane block

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Suprainguinal fascia iliaca (SIFI)

  • Demonstrates supra-inguinal approach

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Femoral nerve

  • Higher risk, involving placement of needle closer to the nerve and vascular structures

Cost analysis & scalability

Materials (Approximate Per-Unit Costs)

  • 3D-printed bone and molds: $4 - 5 (molds are reuseable)

  • Silicone soft tissue layers: <$6 (if purchased by gallon)

  • Ballistic gel or gelatin-based muscle: ~$4

  • Embedded nerve elements: <$0.50 (optional)

  • Total material cost per model: ~$15

(Excludes labor, prototyping, and countless iterations)

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Cost Compared to Alternatives

Commercial ultrasound simulators

  • $3,000 - $20,000+

  • Often limited needle durability

  • Repairs require manufacturer involvement

Cadaver-based training

  • High per-session cost

  • Limited access and reusability

  • Logistical and ethical constraints

  • Constrained to academic and military settings

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Cost-Saving Design Features

  • Reheatable tissue closes needle tracts

  • Underwater use further improves appearance of needle tracts

  • Modular construction avoids full replacement

  • Commonly available materials

  • Printed using basic 3D printers available at many public libraries

  • No proprietary consumables required

Gallery of simulated anatomy

Fascia iliaca block
Video demonstrates needle guidance

SIFI anatomy
Video demonstrates tissue reaction to probe pressure

Femoral nerve and artery
Important landmarks: pelvic brim (bone) and psoas tendon

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PENG block

Important landmarks: pelvic brim (bone) and psoas tendon

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Thanks for submitting!

References

References

Clinical Evidence; PENG & Fascia Iliaca Blocks for Hip Analgesia

  1. Esteller PG, Espinós Ramírez C, Juarez-Pomes M, et al. PENG Block: A superior alternative for pain management in intracapsular hip fractures. Saudi J Anaesth. 2025;19(2):251-256. PMID: 40255360.

  2. DiPietro, et al. Comparing the pericapsular nerve group block and fascia iliaca block for acute pain management in patients with hip fracture: a randomised clinical trial. Anaesthesia. 2025; (randomized ED setting). PMID: 40727959.

  3. Dolstra, et al. PENG, fascia-iliaca compartment block or femoral nerve block for pain management of patients with hip fractures: systematic review. (17 studies, PENG vs FICB/FNB). PMID: 40513549.

  4. Brueggman, et al. Fascia iliaca compartment block and pericapsular nerve group block effect on opioid consumption in hip fracture patients. Retrospective comparison showing lower MME with blocks vs no block. PMID: 40809304.

  5. Foss NB, Kristensen BB, Bundgaard M, et al. Fascia iliaca compartment blockade for acute pain control in hip fracture patients: randomized, placebo-controlled trial. Anesthesiology. 2007;106:773-778. PMID: 19690943.

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Opioid Reduction & Delirium / Cognitive Outcomes

  1. Arnold R, et al. Ultrasound-Guided Regional Anesthesia by Emergency Physicians for Hip Fractures and Delirium. JAMA Netw Open. 2025;8(12):e2842817.

  2. Reduction of Postoperative Delirium and Opioid Use in Hip Fracture Patients with Fascia Iliaca Block.

  3. Simic, et al. Regional nerve blockade for early analgesic management of elderly hip fracture patients. (PMC9536168).

  4. Umbrella review/meta-analysis (Cureus): Regional anesthesia improves pain management, reduces opioid use, and decreases delirium and adverse events in hip fracture surgery.

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Ultrasound Phantom Materials; Ballistic Gel, Echogenicity

  1. Silvestri A, Hall T, et al. Building Affordable, Durable, Medium-fidelity Ballistic Gel Phantoms for Ultrasound-guided Nerve Block Training. J Vis Exp. 2023. PMID: 38407270

  2. Gimber LH, et al. Natural ballistic gelatine ultrasound phantoms are suitable for student education and can be produced cheaply and effectively. Acad Radiol. 2023;30(4):e29-e38. PMID: 37036811

  3. Madsen EL, Frank GR, et al. Acoustical properties of selected tissue phantom materials for ultrasound imaging. Ultrasound Med Biol. 2007;33(11):1736-1750. PMID: 17921571

  4. McKelvey DJ, et al. A novel and inexpensive ballistic gel phantom for ultrasound training. Acad Emerg Med. 2015;22(11):E1-E6. PMID: 26401186

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General Background / Technique

  1. Laumonerie P, et al. Peripheral nerve blocks for hip fractures. Pain Med. 2024;25(2): PMID: 38929985.

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© 2026 Julia Lerner

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