# Backslab Application

## Overview

This module describes how to apply a backslab, the preferred method of immobilisation for acute injuries or injuries at a high risk of swelling. Refer here for instructions on how to apply a plaster cast, and here for how to remove a cast.

## Indications

1. Most acute fractures
2. Dislocations after reduction
3. Some congenital deformities
4. Almost all elbow fractures (high risk of swelling)
5. Tibial fractures (high risk of swelling)
6. Most minor wrist fractures
7. Some soft tissue injuries e.g. severe sprains
8. Crush injuries & open fractures

## Contraindications

1. Unstable fractures
2. Most complex fractures

## Patient information & consent

Always verify your patient’s identity and obtain informed consent before proceeding.

### How do I explain this procedure?

“This broken bone will need to stay completely still for a few weeks to heal. In some cases, it is better to use a splint than a full cast, for example, when there is still swelling. However, a splint can be more easily damaged. We may replace the splint with a full cast after a while.”

### What can my patient expect?

“I’m going to wrap a few layers of bandages around your limb, then put on some layers of plaster that will harden within a few minutes. The splint may feel warm as it hardens. It will take a day to be fully hardened.”

### What is my patient’s role?

“Let me know if you feel any areas where the splint is pressing against you too hard, or where it feels uncomfortable or painful. While the splint is still hardening today, try not to move your limb around too much. Come back to the clinic tomorrow for a check, and after x weeks, come back again so we can remove the cast. Don’t let your splint get wet or dirty, and don’t remove it.”

## Preparation

X-rays should be taken before splinting, and the degree of displacement should be assessed.

Undisplaced or minimally displaced fractures usually do not require reduction. Displaced fractures need to be reduced by longitudinal traction, followed by exaggerating the displacement, and then three-point pressure to reduce the displacement while the splint is being applied.

Prepare a trolley with equipment. An assistant is essential to hold the limb in place.

### Documentation

1. Patient notes

### Equipment

1. Non-sterile gloves
2. Alcohol-based hand rub
3. Plastic apron
4. Orthopaedic padding (OrthoWool)
5. Stockinette
6. Elastic crêpe bandage
7. Scissors
8. Plaster of Paris (generally broader rolls for lower limbs and narrower for upper limbs)
9. Bucket of lukewarm water

## Site & Positioning

The type of fracture dictates the position in which a limb is immobilised.

Thumb spica splint: forearm in neutral position, wrist in 25° extension, thumb in position of function (holding a can). Apply the splint ​​from the proximal one third of the forearm to just distal to the interphalangeal joint of the thumb.

Dorsal/volar forearm splint: forearm in neutral position, wrist neutral. The splint is applied from the mid-forearm to the distal palmar crease.

Below elbow splint: forearm in neutral position, wrist neutral or slightly flexed. The splint is applied from the proximal forearm to the proximal palmar crease.

Above elbow splint: forearm in neutral position, elbow bent 90°, wrist neutral or slightly flexed. The splint is applied posteriorly from the proximal upper arm just beneath the axilla, to the proximal palmar crease.

Sugar tong splint: forearm in neutral position, elbow bent 90°, wrist slightly extended. The splint is applied from the proximal palmar crease, around the elbow, to just proximal to the knuckles.

Double sugar tong splint: position and apply first splint as for sugar tong splint. The second splint is applied from just distal to the deltoid, around the elbow, to 7 cm short of the axilla.

U-splint: forearm in neutral position, elbow bent 90°. The splint is applied from the AC joint, around the elbow, to 7 cm short of the axilla.

Below knee splint: ankle in neutral. Avoid plantar flexion. The splint is applied from the inner mid-calf, around the heel, to the outer mid-calf.

Above knee splint: ankle in neutral, knee slightly flexed. Avoid plantar flexion. The splint is applied from the mid-thigh to just proximal to the toes.

## Procedure

Follow medical asepsis with nonsterile gloves.

1. Examine the injured limb’s

   neurovascular status.
   neurovascular status.

   Look for colour and capillary refill, feel for temperature and sensation, and ask the patient to move the limb.

2. Under analgesia or sedation, reduce the fracture if required.

3. Cover the injured limb with stockinette, leaving enough to fold over the ends on either side.

4. Wrap the limb in orthopaedic padding. Start and end with a double wrap. As you advance up the limb, make a 50% overlap of each wrap. Around joints, use a figure-8 technique to reduce bulk.

5. Measure the length of plaster required to form the backslab by laying it alongside the patient’s injured limb.

6. Unroll and fold the plaster to create a slab of 12-15 layers of plaster for lower limbs and 8-10 layers for upper limbs.

7. Immerse the slab in the water until it stops bubbling. Lift it out and drain away excess water.

8. Lay the slab along the limb, moulding it with your hands to fit the contours of the limb. An assistant may help to keep the slab in place.

9. Fold down the edges of stockinette to form smooth edges.

10. Catching the edges of the stockinette, wrap the elastic crêpe bandage around the limb with 50% overlap until the entire splint is covered.

11. Hold the limb in position for 5 minutes until the splint is set.

12. Recheck the injured limb’s

    neurovascular status,
    neurovascular status,

    Look for colour and capillary refill, feel for temperature and sensation, and ask the patient to move the limb.

    and repeat the X-ray to confirm reduction.

13. Record completion of the procedure in patient notes.

## Risks

1. Pressure ulcers & infected wounds under the splint
2. Malunion or failure to heal
3. Iatrogenic fractures during reduction
4. Nerve damage
5. Muscle atrophy
6. Complex regional pain syndrome
7. Patient non-compliance and splint removal
8. Arthritis

## References

1. Boyd AS, Benjamin HJ, Asplund C. Splints and Casts: Indications and Methods. Am Fam Physician. 2009 Sep 1;80(5):491-499. Available from: https://www.aafp.org/afp/2009/0901/p491.html
2. Kruger N, Venter P. Plaster of Paris casts. In: Held M, editor. Orthopaedics for Primary Health Care. Available from: https://vula.uct.ac.za/access/content/group/1b893abf-7d9f-43e3-aebc-745161173a9e/Skills/51_Plaster%20application%20-%20final.pdf
3. Vermaak S. How to Apply a Plaster Cast. In: Mash B, Blitz-Lindeque J, eds. South African Family Practice Manual. 2nd ed. Pretoria: Van Schaik Publishers; 2010: 347-348.