Main types of immobilization
In traumatological practice, two basic plaster cast configurations are distinguished:
- Splint cast. A layer of plaster bandages molded to the body contours. It covers at least 2/3 of the volume of the injured segment and is secured with standard gauze or elastic bandages.
- Pros: maintains access to wounds, reduces the risk of compartment syndrome (since the edges can slightly spread apart in case of edema), and allows skin inspection.
- Circular (solid) cast. Provides absolute and maximum rigid fixation.
- Risks: strictly contraindicated in acute injuries or postoperative periods due to inevitable soft tissue edema. An increase in limb volume inside a confined space leads to severe ischemia.
Modifications of the circular cast
To solve specific clinical tasks, solid casts are often modified:
- Splint-circular cast: a splint base rigidly secured with turns of a plaster bandage (immediately or a couple of days after edema subsides).
- Initially incised cast: immediately after the mass hardens, the cast is cut longitudinally to prevent ischemia.
- Fenestrated cast: an opening is cut out to access the wound. Strict rule: the window must not exceed 1/2 of the circumference, otherwise the structure will break.
- Bridged cast: two separate circular cuffs connected by metal bars.
- Specific casts: complex casts for specific areas, for example, thoracobrachialis (thoracobrachialis), coxitis (coxitis), or corset casts.
Key application rules
Mistakes in casting can cost a patient a limb. The physician must strictly follow the protocol:
- Volume of coverage: at least two joints adjacent to the injury site must be rigidly fixed.
- Bandaging technique: turns are rolled from the periphery to the center, strictly without tension. Each new turn overlaps the previous one by 2/3.
- Tissue protection: the edges of the cast are carefully molded so they do not cut into the skin. Soft padding must be placed over bony prominences (ankles, patellae, olecranon processes).
- Blood flow monitoring: the distal phalanges of the fingers are always left open and thoroughly cleaned of plaster crumbs. This is the only way to visually monitor the trophism of the distal parts.
Severe complications
Limb compression is a critical situation. It presents with acute, bursting pain and signs of impaired circulation distal to the cast. Tactics: immediately cut the cast along its entire length and spread the edges apart. A frequent mistake is partial incision, which only increases distal edema. It is important to remember that preserving limb viability is many times more important than the risk of secondary fragment displacement.
Local necrosis is the result of plaster pressure on bony prominences due to folds or poor padding. The patient complains of localized burning pain. Critical nuance: if a pressure sore has already formed, nerve endings die and the pain completely disappears. Therefore, at the slightest suspicion, the cast must be opened and tissues inspected.
Briefly: answers to topical questions
What specific plaster casts are used in traumatology?
Traumatology utilizes specialized plaster casts designed for specific injuries and diseases. These include:
- thoracobrachial cast;
- thoracocranial cast;
- coxitis cast;
- corset cast.
Casts with movable hinges are also used to prevent contractures, as well as serial plaster casts for the treatment of persistent arthrogenic contractures.
What are the rules of the bandaging technique when applying a plaster cast?
When applying a plaster cast, bandaging is performed strictly from the periphery to the center. The main rules of the bandaging technique include:
- Bandage turns are applied without the slightest tension, folds, or kinks, freely unrolling the bandage.
- Bandaging is performed in an overlapping manner like a spiral bandage, with each subsequent turn overlapping the previous one by 2/3.
- Upper turns must not be pulled tighter than the underlying ones.
- After every 2–3 turns, the cast is carefully molded, and each layer is smoothed with the palm of the hand.
- Upon reaching the upper boundary, bandaging is repeated from the distal parts.
It is strictly unacceptable for the bandage edges to dig into soft tissues.
Which bony prominences require mandatory protection with a cotton-gauze pad during casting?
When applying a plaster cast, bony prominences located directly under the skin must be protected from pressure. To prevent chafing, pressure sores, and local soft tissue necrosis, a cotton-gauze pad is used to protect:
- clavicles;
- olecranon processes;
- iliac crests;
- patellae;
- ankles;
- heels.
Pads are placed between the edges of the cast and the skin, and the cast itself is carefully molded in these areas until the contours of the immobilized surface are felt.
What clinical signs indicate impaired blood supply to the distal parts under the cast?
Impaired blood supply to the distal parts under a plaster cast is indicated by a combination of local and general symptoms. Clinical signs of compression include:
- severe local pain and a bursting sensation;
- swelling of the fingers;
- bluish (cyanotic) skin discoloration;
- coldness of the distal parts;
- sensory impairment;
- limitation of active movements.
General signs of increasing ischemia include tachycardia and fever. If these symptoms appear, the bandage must be urgently cut along its entire length.
What are the absolute contraindications to applying a solid circular plaster cast?
The application of a solid circular plaster cast should be avoided when there is a high risk of increasing edema, specifically:
- in recent trauma;
- following traumatic manipulations;
- after surgical interventions.
As edema increases, a circular cast can cause severe ischemic disorders, up to and including ischemic contractures and limb necrosis.
The "Two-Thirds" rule for casting: a reliable splint must cover at least 2/3 of the limb volume, and each subsequent turn of the circular bandage must overlap the previous one by 2/3 of its width.
Class and exam questions
Why are the tips of the fingers left open during casting?
This is necessary for continuous visual monitoring of tissue trophism. By assessing the color, temperature, and sensitivity of the fingers, the physician evaluates the blood supply and innervation of the distal parts of the limb beneath the cast.
What to do if severe pulsating pain develops under a solid cast?
It is necessary to urgently cut the circular cast along its entire length and spread the edges. Waiting for the edema to subside is unacceptable—this will lead to ischemic contracture or complete necrosis of the segment.
Can a circular cast be applied immediately after the reduction of a fresh fracture?
No. In recent trauma, the development of pronounced edema is inevitable. The closed loop of a circular cast will create a tourniquet effect. Using a splint is recommended.
What else to study on this topic
- Technique of serial casting in the treatment of arthrogenic contractures
- Anatomic landmarks of bony prominences requiring mandatory protection
- Indications for a thoracocranial (thoracocranialis) cast
- Alternatives to plaster: modern hinged orthoses and splint-sleeve apparatuses
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