Immobilisation - Long arm backslab
Indications
Fractures of:
Radial shaft
Ulnar shaft
Elbow
Distal humeral
Contraindications (absolute in bold)
None
Alternatives
Open reduction with internal fixation
Informed consent
Verbal consent
Less complex non-emergency procedure with low risk of complications
Potential complications
Failure (reduction or immobilisation)
Thermal burns (from heat released during setting of plaster)
Neurovascular compromise
Pruritis
Dermatitis
Abrasions and pressures sores (with risk of infection)
Joint stiffness
Procedural hygiene
Standard precautions
PPE: non-sterile gloves, apron
Area
Plaster room or bed space
Staff
Procedural clinician and assistant
Equipment
Stockinette (optional)
7.5cm cotton padding (slightly narrower than arm diameter)
15cm plaster for backslab (slightly wider than arm diameter)
10cm plaster for stirrup (approximately arm diameter)
Trauma scissors
Bowl of cold water
Crepe bandages
Tape
Positioning
Sitting with elbow supported on table or by assistant
Assistant maintains position of limb while proceduralist applies plaster
Thumb pointing to own shoulder
Shoulder abducted slightly
Elbow flexed to 90 degrees
Forearm in neutral pronation and supination
Wrist in neutral or slight extension
Cast
Estimate plaster length by laying dry splint next to the uninjured arm
Layers: 8-10 layers along ulnar arm, 10-12 layers for stirrup from axilla to axilla
Distal margin: distal palmar crease (forearm fracture), proximal to radio-carpal joint (distal humeral fracture)
Proximal margin: 5cm below axilla
Medication
Consider paracetamol 1g, ibuprofen 400mg and oxycodone 5mg (pain relief one hour pre-procedure)
Consider fentanyl 25-50mcg IV (pain relief pre-procedure adjusted to co-morbid status)
Consider fentanyl 100mcg IV (1.5mcg/kg pain relief pre-procedure adjusted to co-morbid status)
Sequence
Ensure adequate analgesia prior to procedure
Inspect the extremity prior before splinting, document lesions repairing or dressing as normal
Apply stockinette to arm beyond margins of plaster (allowing folded to a smooth edge)
Cut a small hole in stockinette for thumb
Apply 2-3 layers of cotton padding beyond plaster margins
Tear or cut cotton padding as it passes through the first webspace
Ensure elbow is well padded and padding overlaps itself by 25-50% with minimal creases
Submerge the pre-prepared dry backslab in water until bubbling stops, then remove
Squeeze out excess water, smooth on a flat surface and apply along ulnar border of forearm
Submerge the pre-prepared dry stirrup splint in water until bubbling stops, then remove
Squeeze, smooth apply along the lateral aspect of forearm extending around elbow to medial axilla
Turn back padding around distal and proximal margins of plaster
Apply crepe bandage firmly over slab and fasten with tape
Gently mould plaster to patient anatomy (palm particularly) maintaining wrist and elbow position until hardened
Post-procedure care
Check X-ray, circulation and limb function:
Confirm fracture reduction with post-procedure X-ray
Check capillary refill and comfort (loosen crepe bandage or re-splint if required)
Check plaster is in correct position at elbow and wrist
Check full MCPJ flexion and extension of digits 1-5 or radio-carpal joint, depending on distal margin of plaster
Provide plaster care instructions:
Elevate limb when possible using a collar and cuff sling (decreases pain and swelling)
Avoid applying pressure and heat to the cast
Do not wet the plaster (use plastic bag to protect plaster while in shower)
Return for assessment if damaged cast, increasing pain, numbness or skin colour changes
Provide temporary cast plaster care patient fact sheet
Tips
Temporary casting of open fractures requires covering open wounds with saline-moistened sterile gauze
Always use clean cold water (avoiding thermal injury and allowing for 10 minutes moulding time)
Extra padding at bony prominences avoids pressure areas (olecranon, radial and ulnar styloid)
All backslabs are temporary requiring definitive management after two weeks (e.g. full cast)
Discussion
There are a variety of splinting techniques in common emergency department practice. Indications for specific casts and recommended methods of application may vary depending on your institution. If in doubt seek local advice from an experienced provider or discuss with your orthopaedic team.
Peer review
This guideline has been reviewed and approved by the following expert groups:
Emergency Care Institute
Please direct feedback for this procedure to ACI-ECIs@health.nsw.gov.au.
References
NSW Agency for Clinical Innovation. Orthopaedic/musculoskeletal. Sydney: ACI; 2020. Available from https://www.aci.health.nsw.gov.au/networks/eci/clinical/clinical-resources/clinical-tools/orthopaedic-and-musculoskeletal
Roberts JR, Custalow CB, Thomsen TW. Roberts and Hedges’ clinical procedures in emergency medicine and acute care. 7th ed. Philadelphia, PA: Elsevier; 2019.
Dunn RJ, Borland M, O’Brien D (eds.). The emergency medicine manual. Online ed. Tennyson, SA: Venom Publishing; 2019.
Eiff MP, Hatch R. Fracture management for primary care. 3rd ed. Philadelphia PA: Saunders; 2011.
Stracciolini A. Basic techniques for splinting of musculoskeletal injuries In: UpToDate. Waltham (MA): UpToDate. 2019 April 18. Available from: https://www.uptodate.com/contents/basic-techniques-for-splinting-of-musculoskeletal-injuries
Liverpool hospital emergency department: Plaster booklet (2019)