How to perform a digital nerve block - toe
Source
Surgeon:
Hannu Kuokkanen (plastic surgeon)
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Summary
Focus: Local anesthesia for procedures of the toe.
Key elements: Small-gauge needle use, gradual anesthetic injection, plantar digital nerve coverage, waiting for anesthesia, and testing before the procedure.
Indications and Clinical Context
General
Medical experts: Hannu Kuokkanen (plastic surgeon), Jenni Liikanen (orthopedic resident)
Name of Procedure: Digital Nerve Block - Toe
Goal of Operation
Perform local anesthesia to facilitate procedures of the toe such as wound or tendon suturing, toe amputation, or fracture treatment.
Problem
Pain management in toe procedures.
Key anatomical structures
Digital nerves
Dorsal and plantar branches
Digital arteries
Proximal phalanx
Step-by-Step Technique
Step-by-Step Technique
Use a small-gauge needle to minimize pain. Preferably, use a Luer-lock syringe, so that the needle is screwed onto the syringe and will not come off. The local anesthetic used is usually 10–20 mg/ml (1–2%) lidocaine without adrenaline.
Firmly grasp the toe and tighten the skin with your fingers to prevent the skin slipping.
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Puncture the skin and, immediately after skin puncture, start injecting a small amount of anesthetic so that the tissue where the needle is advancing is already pre-anesthetized, reducing the patient’s pain. The anesthetic solution itself also pushes the nerves and vessels aside and there is less risk of e.g. puncturing the needle painfully to the digital nerves.
Gently inject a small amount of anesthetic each time you advance. Advance close to the periosteum of the proximal phalanx and all the way very close to the plantar skin, so that the anesthetic also numbs the plantar digital nerves.
As you withdraw the needle, inject more anesthetic to make the skin bulge. Here, a few millilitres of anesthetic solution have been injected.
Repeat the procedure on the other side of the toe.
Wait for 15 minutes and test the anesthesia with a needle prick to the tip of the toe.
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Piftalls and Complications
Pitfalls
Careless tissue handling
A toe nerve block is usually quite painful to the patient. To relieve the pain, advance determinably through the skin and, immediately after passing the skin, start injecting the anesthetic. This way, the soft tissue where the needle is advancing is pre-anesthetized causing less pain. In addition, the anesthetic solution itself also pushes the nerves and vessels aside, decreasing the risk of puncturing them and causing excess pain and / or bleeding.
Being too hasty
It is essential to wait about 10–15 minutes to give time to the anesthesia to work before the procedure.
Complications
Nerve or vessel injury
There is a risk of puncturing the digital nerve or digital artery with the needle. Puncturing the nerve is extremely painful to the patient. It may also cause prolonged pain in the form of neuropraxia (segmental demyelination of the nerve).
Puncturing the artery causes excess bleeding and risk of injecting the anesthetic into the vessel. You can minimize these risks by injecting the anesthetic immediately after passing the skin so that the anesthetic solution itself pushes the nerves and vessels aside.
Neurolysis
Neurolysis is a rare complication due to the injected solution causing chemical injury. Always check yourself that you are injecting the appropriate local anesthetic with the right concentration.
FAQ
What local anesthetic is usually used for a toe digital nerve block?
The local anesthetic used is usually 10–20 mg/ml (1–2%) lidocaine without adrenaline.
How long should you wait before testing the anesthesia?
Wait for 15 minutes and test the anesthesia with a needle prick to the tip of the toe.
Why should anesthetic be injected immediately after passing the skin?
Injecting the anesthetic immediately after passing the skin pre-anesthetizes the soft tissue where the needle is advancing, causing less pain. The anesthetic solution itself also pushes the nerves and vessels aside, decreasing the risk of puncturing them.
What complications can occur from puncturing the digital nerve or artery?
Puncturing the nerve is extremely painful and may cause prolonged pain in the form of neuropraxia. Puncturing the artery causes excess bleeding and risk of injecting the anesthetic into the vessel.
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