Advanced Biomechanical Analysis High-Energy Dorsal Hand Avulsion After Vehicular Drag Injury DrRamonReyesMD – 2026

 

⚠️ Warning: The images depict severe traumatic injuries with extensive tissue exposure. The following description is strictly medical-academic.

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🩺 Clinical Case: Complex Dorsal Hand Avulsion Reconstructed with an Abdominal Flap

Sequential descriptive analysis
DrRamonReyesMD – 2026

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📷 IMAGE DESCRIPTION (in order)

🔹 Image 1/5 – Initial post-trauma phase

An extensive dorsal avulsion of the hand and wrist is observed, with near-total loss of cutaneous and subcutaneous coverage.
Relevant features:

• Exposure of extensor tendons and osteoarticular structures.
• Initial debridement with clearly devitalized tissue.
• “Road rash” abrasion components consistent with an asphalt-friction shear mechanism.
• Probable involvement of the extensor retinaculum.
• Areas of cutaneous and muscular necrosis.

The injury is compatible with a high-energy vehicular dragging mechanism, producing a mixed pattern of:

• Avulsion
• Degloving
• Thermal and mechanical friction injury

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🔹 Image 2/5 – Expanded debridement and structural assessment

The hand is seen after more aggressive surgical debridement:

• Frank exposure of metacarpals.
• Extensor tendons partially preserved or transected.
• Possible periosteal injury.
• Controlled hemostasis.
• Preparation of the recipient bed for vascularized coverage.

Primary objectives here:

• Remove necrotic tissue.
• Reduce bacterial load.
• Assess viability of deep structures.

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🔹 Image 3/5 – Osseous reconstruction and stabilization

Kirschner wires (K-wires) are observed, used for:

• Fixation of metacarpal fractures.
• Carpal stabilization.
• Alignment of phalanges.

This stage corresponds to early skeletal stabilization, essential prior to definitive soft-tissue coverage.

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🔹 Image 4/5 – Abdominal flap (groin/abdominal flap)

The hand is sutured to the patient’s abdomen:

• Pedicled abdominal flap.
• Temporary perfusion support for revascularization.
• Provisional coverage of exposed tissues.
• Goal: allow secondary neovascularization.

This is a classic reconstructive technique when:

• There is no immediately viable local recipient bed.
• Free-flap microanastomosis is not feasible.
• Robust vascularized coverage is required.

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🔹 Image 5/5 – Late reconstructive phase

Identified elements include:

• Flap division.

• Tendon reconstruction.

• Placement of silicone rods (Hunter-type staged tendon reconstruction technique) to:

  • Create fibrous tunnels.
  • Facilitate future second-stage tendon reconstruction.

• Multiple integration sutures.

This corresponds to staged surgery:

1. Coverage
2. Maturation
3. Functional reconstruction
4. Intensive rehabilitation

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🧠 PROCEDURAL ANALYSIS IN CONTEXT

Mechanism of injury

Patient struck and dragged with the upper extremity trapped beneath the body.
Predominant mechanism:

• Friction-related shear
• Dorsal avulsion
• Crush component
• Possible associated neurovascular injury

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Surgical strategy applied

1️⃣ Initial control

• Wide debridement
• Pulsatile irrigation
• Hemostasis
• Broad-spectrum antibiotics
• Tetanus prophylaxis

2️⃣ Skeletal stabilization

• K-wire fixation
• Restoration of length and alignment
• Protection of metacarpal arch integrity

3️⃣ Vascularized coverage

Use of a pedicled abdominal flap to:

• Provide robust vascularity
• Cover exposed bone and tendons
• Reduce osteomyelitis risk
• Preserve tissue viability prior to finer reconstruction

4️⃣ Two-stage tendon reconstruction

Silicone rod placement:

• Pseudosheath formation
• Second stage: autologous tendon grafting
• Goal: restore active extension

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🩸 Critical considerations

• High risk of deep infection
• Risk of early compartment syndrome
• Need for prophylactic anticoagulation
• Multimodal pain control
• Early guided rehabilitation

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🎯 Functional prognosis

Will depend on:

• Neurovascular integrity
• Degree of superficial radial nerve and median nerve injury
• Flap quality
• Postoperative adhesions
• Compliance with intensive physiotherapy

Realistic goals in injuries of this magnitude:

• A supportive/assistive hand
• Partial recovery of extension
• Preservation of thumb function and pinch

⚠️ Medical content involving complex trauma. Academic analysis.

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🔬 Deep Anatomical Analysis

Complex Dorsal Avulsion of the Hand and Wrist

Advanced level 2026 – DrRamonReyesMD

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I. INJURY CONTEXT

The observed pattern corresponds to a high-energy dorsal avulsion with a degloving component and asphalt-friction shear.

This type of injury damages multiple anatomical planes simultaneously, potentially involving:

• Skin
• Subcutaneous tissue
• Fascial layers
• Tendons
• Osteoperiosteal structures
• Potential neurovascular injury

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II. NORMAL DORSAL ANATOMY (Reference)

To understand injury magnitude, review the layered organization:

🔹 1️⃣ Dorsal skin

• Thin
• Highly mobile
• Minimal adipose tissue

🔹 2️⃣ Subcutaneous tissue

• Superficial vascular supply
• Dorsal venous plexus

🔹 3️⃣ Dorsal venous system

• Prominent superficial venous network
• Drainage toward cephalic and basilic veins

🔹 4️⃣ Extensor retinaculum

A transverse fibrous structure at the wrist that:

• Maintains extensor tendons within their compartments
• Prevents “bowstringing”

🔹 5️⃣ Extensor compartments (6 dorsal compartments)

1. Abductor pollicis longus (APL)
2. Extensor carpi radialis longus/brevis (ECRL/ECRB)
3. Extensor pollicis longus (EPL)
4. Extensor digitorum communis (EDC)
5. Extensor digiti minimi (EDM)
6. Extensor carpi ulnaris (ECU)

🔹 6️⃣ Osteoperiosteal plane

• Metacarpals
• Carpal bones
• Highly vascular periosteum

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III. ANALYSIS OF COMPROMISED STRUCTURES

🩸 1️⃣ Cutaneous and subcutaneous compromise

Dorsal avulsion removes the natural protective coverage.

Consequences:

• Loss of antimicrobial barrier
• Exposure of tendons (without viable paratenon)
• High risk of secondary necrosis

In this case:
✔ Extensive dorsal skin loss
✔ Devitalized subcutaneous tissue
✔ Asphalt contamination

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🧵 2️⃣ Tendon compromise

Extensor tendons are especially vulnerable because:

• They are superficial
• They lack significant muscular protection
• They rely on paratenon for nutrition

Observed features may include:

• Partial or complete EDC transection
• Possible EPL injury
• Extensor retinaculum disruption

Without vascularized coverage: exposed tendons necrose within days.
Hence the abdominal flap.

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🦴 3️⃣ Osteoperiosteal injury

Dragging mechanisms can cause:

• Periosteal stripping
• Shear fractures
• Superficial cortical loss

When periosteum is lost:

• Osteogenic capacity decreases
• Osteomyelitis risk increases

K-wires:
✔ Restore alignment
✔ Maintain metacarpal length
✔ Provide stability before coverage

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⚡ 4️⃣ Potential neurovascular compromise

Structures at risk:

• Superficial radial nerve branch
• Dorsal metacarpal arteries
• Superficial venous arches

If the superficial radial nerve is transected → dorsal sensory loss and chronic neuropathic pain.

No microanastomosis is evident in the images, suggesting:

• Primary inflow likely preserved via the palmar arch.

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IV. PATHOPHYSIOLOGY OF DRAG-RELATED INJURY

This trauma type produces:

🔥 1. Secondary thermal friction injury

Heated asphalt induces microscopic thermal damage.

🩸 2. Shear injury

Separation of anatomical planes.

🦴 3. Crush injury

Sustained tissue compression.

🧫 4. High bacterial load

Environmental contamination.

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V. ANATOMICAL RATIONALE FOR ABDOMINAL FLAP USE

When the dorsal hand loses:

• Skin
• Subcutaneous tissue
• Paratenon
• Periosteum

The following are not viable:

❌ Simple skin graft
❌ Primary closure

What is required:

✔ Vascularized tissue
✔ Adequate thickness
✔ Ability to cover exposed bone

The abdominal flap provides:

• Robust perfusion
• Malleable tissue
• Durable coverage

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VI. TWO-STAGE TENDON RECONSTRUCTION

Silicone rod placement enables:

1️⃣ Formation of a fibrous tunnel
2️⃣ A prepared environment for secondary tendon grafting

Without this:

• Massive adhesions form
• Extensor mobility is lost

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VII. EXPECTED ANATOMICAL COMPLICATIONS

• Metacarpophalangeal stiffness
• Extensor adhesions
• Complex regional pain syndrome
• Deep infection
• Partial functional range loss

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VIII. REALISTIC FUNCTIONAL PROGNOSIS

In injuries of this magnitude:

✔ Primary goal: salvage the hand
✔ Secondary goal: restore pinch
✔ Tertiary goal: functional mobility

Complete restoration is unlikely, but achievable outcomes may include:

• Assistive functional hand
• Supportive pinch
• Moderate grip capacity

⚠️ Professional technical analysis. Major upper-extremity trauma. Operational approach 2026.

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🛡 OPTIMAL PREHOSPITAL MANAGEMENT

Complex dorsal avulsion of the hand and wrist

TECC / TACMED approach – Advanced Level 2026
DrRamonReyesMD

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I. IMMEDIATE PREHOSPITAL PATHOPHYSIOLOGY

A high-energy dorsal avulsion from vehicular dragging combines:

• 🔥 Thermal friction injury
• 🩸 Mixed hemorrhage (arterial + venous + osseous)
• 🧠 Extreme nociceptive pain
• 🦴 Osteoarticular instability
• 🧫 Massive contamination

Immediate risk is not only functional loss; it includes:

1. Hemorrhagic shock
2. Pain-mediated shock physiology
3. Mixed shock in multisystem trauma

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II. TECC PRIORITIES

🔴 DIRECT THREAT CARE (unsafe scene)

Goal: immediate survival

1️⃣ Rapid extraction
2️⃣ Immediate hemorrhage control
3️⃣ Move to a safer zone

In this type of injury:

✔ Pulsatile uncontrolled bleeding → proximal tourniquet (TQ) on the arm
✔ Diffuse venous bleeding → direct pressure with hemostatic dressing

Important: dorsal hand bleeding may appear less dramatic, but open fractures can conceal significant hemorrhage.

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🟡 INDIRECT THREAT CARE

Transition to advanced care.

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III. HEMORRHAGE CONTROL

🔹 1. Vascular assessment

Check:

• Radial pulse
• Capillary refill
• Deep active bleeding
• Distal pallor

Absent pulse → consider proximal arterial injury.

🔹 2. Tourniquet: yes or no?

Indications:

✔ Uncontrolled arterial hemorrhage
✔ Hemodynamic instability
✔ Multiple casualties

Relative contraindication:

❌ Distal injury controllable by compression

In many dorsal avulsions: compression + pressure dressing is sufficient, unless a major arterial injury exists.

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IV. PAIN MANAGEMENT (strategic priority)

Severe pain increases:

• Oxygen consumption
• Catecholamine surge
• Shock risk

Modern 2026 approach:

🔹 Option 1: Ketamine IV or IM

• 0.2–0.3 mg/kg IV (analgesia)
• 0.5–1 mg/kg IM (if no IV access)

Advantages:
✔ Hemodynamic stability
✔ Minimal respiratory depression
✔ Ideal for major trauma

🔹 Option 2: Titrated IV fentanyl

Only if stability is ensured.

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V. IMMOBILIZATION

Goals:

• Reduce pain
• Prevent further tendon damage
• Reduce osseous bleeding

Technique:

✔ Rigid forearm–palmar splint
✔ Hand in functional position
✔ Moderate elevation if no vascular compromise

Avoid:

❌ Unnecessary manipulation
❌ Aggressive field irrigation

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VI. CONTAMINATION CONTROL

Do NOT perform extensive wound washing on scene.

Only:

✔ Cover with sterile moist dressing (normal saline)
✔ Avoid desiccation
✔ Protect exposed structures

Exposed tendons lose viability rapidly when dried.

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VII. SYSTEMIC TRAUMA ASSESSMENT

A dragged patient is multisystem trauma until proven otherwise.

Assess:

• Head injury
• Thoracic injury
• Occult fractures
• Abdominal trauma

Never fixate solely on the hand.

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VIII. PREHOSPITAL ANTIBIOTICS (advanced protocols)

If prolonged transport (>60 min):

✔ IV cefazolin
✔ Add broader coverage if contamination is massive

This reduces deep infection risk.

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IX. DESTINATION CRITERIA

This patient must go to a center with:

• Hand surgery
• Microsurgery capability
• Reconstructive resources
• Trauma service

Not appropriate for a facility without reconstructive capacity.

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X. CRITICAL ERRORS TO AVOID

❌ Inadequate pain control
❌ Failure to protect exposed structures
❌ Aggressive field irrigation
❌ Removing “apparently dead” tissue prehospital
❌ Underestimating vascular injury

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XI. TACTICAL OPERATIONAL SUMMARY

1. Scene safety
2. Immediate hemorrhage control
3. Effective analgesia (ketamine preferred)
4. Functional splinting
5. Sterile moist protection
6. Multisystem assessment
7. Priority transfer to specialized center

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XII. IMPACT ON OUTCOME

Correct prehospital management can:

✔ Reduce secondary necrosis
✔ Improve tendon viability
✔ Reduce infection
✔ Increase reconstructive success likelihood

Time equals tissue.

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⚠️ Advanced biomechanical analysis – Vehicular dragging injury causing dorsal hand avulsion

Technical level 2026 – Surgical and prehospital approach
DrRamonReyesMD

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I. INJURY CONTEXT

Mechanism described:

Patient struck by a vehicle and dragged with the arm trapped beneath the body.

This generates a highly specific injury pattern:

• Sustained tangential friction
• Shear forces
• Axial compression
• Forced rotation
• Thermal transfer from friction

It is not a simple direct impact.
It is a combined high-energy injury with deep abrasive components.

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II. PHYSICAL DYNAMICS OF THE MECHANISM

1️⃣ Initial impact phase

The vehicle transmits:

• Kinetic energy proportional to mass × velocity²
• Anteroposterior vector force

The upper limb typically assumes:

• Reflex extension
• Forced pronation
• Dorsal contact with asphalt

Immediate results:

• Compression fractures
• Possible radiocarpal dislocation
• Capsuloligamentous rupture

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2️⃣ Drag phase

This is where critical tissue destruction occurs.

🔥 A. Dynamic friction

High asphalt–skin friction coefficient generates:

• Local thermal energy
• Protein denaturation
• Thermal abrasion necrosis

Dorsal skin is thinner → lower resistance.

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🩸 B. Shear forces

Asphalt “grips” the skin while the body continues moving, producing:

• Cutaneous avulsion
• Dermal–subcutaneous separation
• Extensor retinaculum detachment
• Metacarpal exposure

Biomechanics:

Tangential force > dermofascial binding strength
→ Deep cleavage plane

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🦴 C. Osseous compression + cortical scraping

The text notes that bones were “shaved,” implying:

• Direct bone–asphalt contact
• Cortical wear
• Abrasion fractures

This rare pattern is described in:

• Motorcycle crashes
• Urban dragging
• Industrial injuries

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III. RESULTING ANATOMICAL PATTERN

Dorsal hand exposure with:

✔ Denuded extensor tendons
✔ Total loss of dorsal skin coverage
✔ Periosteal compromise
✔ Bone fragmentation
✔ Massive contamination

Biomechanics explains why:

• Flexors are often preserved (protected palmar surface)
• Extensors are most affected
• Superficial venous network is destroyed

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IV. ROTATIONAL COMPONENT

During dragging:

• Shoulder rotates
• Elbow partially flexes
• Wrist undergoes torsion

This generates:

• Combined radiocarpal injuries
• Intercarpal ligament damage
• Possible superficial radial nerve injury

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V. ENERGY TRANSFER

Damage is not only superficial.

There is:

🔺 Residual kinetic energy to deep tissues
🔺 Microischemia from traumatic vasospasm
🔺 Secondary compartment edema

Delayed compartment syndrome risk is real.

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VI. BIOMECHANICAL DIFFERENTIATION

Comparison:

• Crush → deep necrosis + edema
• Sharp → defined edges
• Projectile → cavitation
• Drag → avulsion + thermal abrasion + cortical scraping

This case matches the fourth pattern.

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VII. SURGICAL IMPLICATIONS DERIVED FROM BIOMECHANICS

Biomechanics explains decisions such as:

✔ Abdominal or groin flap
✔ Temporary skeletal fixation
✔ Delayed tendon reconstruction
✔ Silicone rods to create tunnels

The tissue is not simply exposed.
It is biologically compromised by mechanical and thermal energy.

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VIII. MECHANISM-DEPENDENT PROGNOSTIC FACTORS

Better if:

• Short dragging time
• Moderate speed
• Early hemorrhage control
• Early coverage

Worse if:

• Prolonged dragging
• Severe contamination
• Delayed surgery
• Proximal vascular compromise

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IX. BIOMECHANICAL SUMMARY

The mechanism combines:

1. Initial kinetic impact
2. Thermal abrasive friction
3. Deep dermal shear
4. Cortical osseous scraping
5. Secondary articular torsion

High-energy mixed-pattern abrasional–avulsive–compressive injury.

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DrRamonReyesMD – 2026