Material
- Syringes 2 ml and 5 ml.
- Aspiration needle.
- Fine needle.
- Local anaesthetic without epinephrine (lidocaine 1% or 2%).
- Disinfectants.
- In medicine chest:
- Tavegil®; 2 mg = 2 ml i.v.
- Dexamethasone 5 ml = 1 ml i.v.
- Epinephrine 1 mg = 1 ml, 0.3 ml i.m.
Procedure
- Ask the patient about allergies for iodine and/or local anaesthetic.
- Tell the patient what you are about to do.
- Ask the patient to lie down.
- Aspirate 2 ml of local anaesthetic (if an assistant prepares the syringe, always check the bottle).
- Disinfect the area to be injected.
- The point of entry for the fine needle is dorsal to one side of the phalanx base, distal to the metacarpophalangeal or metatarsophalangeal joint [Figure 12].
Figure 12
- The direction in which the needle is injected is from dorsal to palmar (or plantar).
- Infiltrate by injecting about 0.5 ml towards the bone at the level of the dorsal sensory nerve branch [Figure 13-1].
- Inject slowly to ensure that no excessive tension in the tissue develops.
- Insert the needle deeper in the volar direction and inject at the level of the volar sensory nerve branch again 0.5 ml of local anaesthetic (the skin is unyielding here, so additional liquid causes high mechanical pressure; as a result, impaired circulation and pain can occur) [Figure 13-2].
- Retract the needle to the point just under the skin.
- Using the original point of entry, insert the needle dorsal to the phalanx, under the skin, over to the other side of the finger (or toe) and create a subcutaneous depot of 0.5 ml at the height of the subsequent second point of entry
[Figure 13-3]. - Anaesthetise according to steps 6-9 the dorsal and volar sensory nerve on the contralateral side of the phalanx [Figure 13-4, 13-5].
- Wait 5-10 minutes for the anaesthesia to take effect completely.
Figure 13