Tibial Intraosseous Access in Combat Zones: Radiological Analysis and Clinical Considerations By DrRamonReyesMD

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Tibial Intraosseous Access in Combat Zones: Radiological Analysis and Clinical Considerations

By DrRamonReyesMD

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Introduction

Intraosseous intravenous (IO-IV) access is a critical technique for resuscitation in emergency situations, particularly in tactical and military environments where peripheral venous access may be impossible due to hypovolemic shock, hypothermia, or circulatory collapse.

Preferred insertion sites include the sternum and the proximal tibia, given their accessibility, predictable anatomy, and ease of identification even under low-visibility conditions.

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Methodology and Context

During autopsy procedures at the Dover Air Force Base Mortuary, computed tomography (CT) imaging was performed on combat casualties who had received IO-IV devices. These scans allowed for precise evaluation of needle location, documenting insertion errors and their impact on clinical effectiveness.

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Results and Main Findings

1. Correct intraosseous placement

• The needle tip must be located in the medullary cavity of the tibia.
• In this position, fluid infusion enters directly into the medullary venous plexus, ensuring rapid and effective absorption.
• Imaging studies demonstrate immediate dispersion of contrast within the bone marrow when the device is correctly positioned.

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2. Common insertion errors

a) IO-IV not in bone

• Insertions from the lateral aspect of the tibia may traverse soft tissue without contacting cortical bone.
• Cause: the lateral tibial surface is curved, making perpendicular insertion difficult.
• Consequence: the device remains in soft tissue, resulting in ineffective vascular access.

b) IO-IV in tibial cortex, not medullary cavity

• Insertions from the medial surface placed too low relative to the flat tibial plateau area.
• Result: the needle impacts the thick anterior cortex without entering the marrow cavity.
• Consequence: fluid does not reach the venous plexus, rendering infusion ineffective.

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3. Incidence of failures

• In over 90% of reviewed cases, tibial IO-IV needles were correctly positioned (unpublished data).
• However, two scenarios consistently resulted in device failure:
  1. Needle outside the tibia (soft tissue).
  2. Needle embedded in the cortex without access to the marrow cavity.

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Anatomical Considerations

• Proximal medial tibial surface: flat and broad, ideal for perpendicular insertion.
• Lateral and anterior surfaces: curved, with thicker cortex, associated with higher risk of malposition.
• The standard insertion site: medial aspect of the proximal tibia, approximately 2 cm below the tibial tuberosity and slightly medial to the tibial crest.

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Clinical Implications in the Tactical Setting

1. Improper IO-IV placement can be fatal, as it prevents rapid resuscitation with fluids, blood products, or medications.
2. In the combat environment, correct anatomical identification is critical under stress, low light, or time-constrained conditions.
3. Training must emphasize perpendicular insertion into the medial proximal tibia and avoidance of lateral or distal deviations.

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Conclusions

• Tibial intraosseous access is a lifesaving tool in combat emergencies.
• Its effectiveness depends on precise placement of the needle within the medullary cavity.
• The most common errors involve lateral insertion into soft tissue or low medial insertion into the thick anterior cortex.
• Radiological evidence confirms the need to reinforce anatomical education and technical proficiency in tactical training.

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Recommendations

• Use the standard insertion site: medial proximal tibia.
• Avoid lateral or distal approaches.
• Confirm placement by aspirating bone marrow or observing free fluid flow without extravasation.
• Conduct periodic retraining of combat personnel in IO-IV procedures.

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✍️ DrRamonReyesMD
Specialist in Emergency Medicine, Tactical Medicine (TACMED) and Aeromedical Evacuation

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