# Digital Block

## Overview

This module describes one technique to anaesthetise a digit.

## Indications

1. Digital anaesthesia for minor procedures

## Contraindications

1. Allergy to anaesthetic agent used

2. Overlying infection

## Patient information and consent

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

### How do I explain this procedure?

“I need to give you an injection that will numb the whole area where we need to work.”

### What can my patient expect?

“I am going to prick your skin twice or three times with a needle and inject the numbing medication. Each injection might sting a bit, but after that the whole area will be numb.”

### What is my patient’s role?

“Let me know if you have any allergies. Fearing blood or needles is normal, but tell me if you have fainted from it. Try to keep your hand still while I give you the injections.”

## Preparation

Prepare a trolley with equipment.

### Documentation

1. Patient notes

### Equipment

1. Non-sterile gloves

2. Sharps container
   Sharps container

   If a sharps container is not within arm's length, use a kidney dish or other hard container to temporarily hold used sharps and to carry them to the sharps container for disposal.

3. Alcohol-based hand rub

4. Dental syringe and

   lignocaine
   lignocaine

   It is current best practice to avoid the use of adrenaline in the penis and digits due to concerns of ischaemia; however, this seems to be controversial in the literature.

   cartridges OR

5. 10 ml syringe, aspiration needle (ideally blunt fill), injection needle & lignocaine vial

6. Alcohol swabs

## Site & Positioning

Position the patient with the digit in question within easy reach.

## Procedure

Follow medical asepsis with non-sterile gloves.

1. Perform hand hygiene and don non-sterile gloves.

2. Check the lignocaine expiry date.

3. Clean the skin with an alcohol swab and allow to dry.

4. Load the dental syringe OR draw up lignocaine in a 10 ml syringe

5. Insert the needle into the dorsal webspace and

   advance
   advance

   across the dorsal aspect of the digit. Aspirate to check for blood if using a regular syringe.

6. While withdrawing the needle back to just under the skin, inject up to 4 ml lignocaine.

7. Advance the needle into the volar webspace across the volar aspect of the digit. Aspirate to check for blood if using a regular syringe.

8. While withdrawing back to the skin, inject up to 4 ml lignocaine.

9. Massage the digit to help distribute lignocaine and wait 5-10 minutes.

10. Dispose of medical waste safely.

11. Record completion of the procedure in patient notes.

## Troubleshooting

My patient is still feeling pain.

Make sure you wait a full 10 minutes before testing the patient’s sensation. If there is still pain, make sure you injected enough anaesthetic into the entire area. Local infection can also reduce the effectiveness of local anaesthetics. Rarely, some patients may be resistant to local anaesthetics.

## Risks

1. Minor pain, bleeding & haematoma

2. Digital ischaemia

3. Intravascular injection

4. Allergic reaction to local anaesthetic

5. Local infection

6. Sharps injury to healthcare personnel

7. Vasovagal response (fainting)

## References

1. Napier A, Howell DM, Taylor A. Digital Nerve Block. [Updated 2021 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526111/

2. Finsen V. Nekrose i fingre og tær etter lokalbedøvelse med adrenalin--en vandrehistorie? [Necrosis in fingers and toes following local anaesthesia with adrenaline--an urban legend?]. Tidsskr Nor Laegeforen. 2013;133(17):1827-1830. doi:10.4045/tidsskr.13.0373