Axillary Nerve Block Injections: Uses, Procedure, Effect Details

Understanding Axillary Nerve Blocks

An axillary nerve block is an anesthetic technique used to induce temporary numbness or loss of sensation in a region of the arm. It works by injecting medication to block the nerves that supply feeling to the upper arm and shoulder area.

Axillary blocks serve an important purpose for allowing comfortable surgery. They also have various other uses for managing significant arm pain. However it’s beneficial to understand more about the procedure, effects of blocking this nerve and what to expect.

Reasons for Getting an Axillary Nerve Block

There are two main medical reasons to temporarily numb the axillary nerve:

1. As anesthesia for arm/shoulder surgery - Axillary blocks provide numbness, allowing procedures like:
• Reducing dislocated shoulders
• Fixing fractured arms/wrists
• Carpal tunnel surgery
• Tendon/ligament repair
• Some skin grafts or plastic surgeries
2. For short-term pain control - The numbness can provide symptom relief for a period of time from:
• Broken arm or shoulder injuries
• Burns or other arm traumas
• Acute flare up of arthritis/tendinitis
• Certain arm surgeries involving stitches or implants

Understanding Axillary Nerve Anatomy

It first helps to review the route of the main nerves supplying upper arm and armpit sensation:

• The axillary nerve originates off the larger brachial plexus nerves roots exiting the neck/spine.
• It runs through the armpit area (axilla) into the shoulder joint and upper humerus bone.
• In the deltoid muscle region, it branches out to innervate the overlying skin and deeper tissues.

When medication is injected to block the axillary nerve, it interrupts signaling along this pathway temporarily. Numbness typically spreads down the arm and into the shoulder area. The deltoid muscle may also weaken until the anesthetic wears off.

Axillary Block Procedures

There are a few techniques to block the axillary nerve for either surgery or pain control. The two main versions used include:

Traditional Landmark-Based Version

For this original version of the axillary block procedure, the patient lies down with the arm held out sideways from the body. The physician identifies anatomical "landmarks" like the artery pulse point to estimate the likely path of the nerve.

After cleaning the skin, a specialized syringe with a short needle is used to inject numbing medication. This follows the expected route to have the highest chance of contacting the nerve. Sometimes nerve stimulation helps confirm proper positioning too.

Ultrasound-Guided Approach

A newer technique for axillary blocks uses ultrasound imaging to visualize the nerves and guide injection. Benefits of ultrasound guidance include:

• Lower medication volumes needed
• Faster onset of numbness
• Longer duration of analgesic effects
• Reduced risk of complication

However, the traditional landmark approach still works reasonably well and has a long track record of safety.

Medications Used

The medications injected to generate temporary numbness may include:

• Lidocaine - Shorter acting local anesthetic.
• Bupivacaine - Longer acting anesthetic, preferred for surgeries.
• Ropivacaine - Related to bupivacaine with less toxicity.
• Corticosteroids - Sometimes mixed in the injection to provide anti-inflammatory effects.

The doctor selects appropriate medication strengths and volumes tailored to the intended duration of the nerve block. The dose gets slowly delivered near the axillary nerve using careful injection technique.

What Does it Feel Like?

When first receiving an axillary nerve block injection, you'll feel the needle enter the skin and may notice mild burning at the injection site.

However within 5-15 minutes, the numbing takes effect. Many people describe odd tingling, buzzing or warmth spreading down from the shoulder towards the hand. The arm then becomes completely numb, limp, and immovable much like after significant dental work.

The extent, intensity and duration of numbness depends on the nerve block technique and medications chosen. Feeling typically returns slowly over a few hours, with the hand regaining sensation before the shoulder area.

Benefits of Axillary Blocks

There are many advantages to using axillary nerve blocks versus general anesthesia or relying only on oral pain pills:

• Very focused numbness - Only the intended arm is anesthetized, allowing faster system clearance.
• Remains conscious - You stay awake and aware, unlike being "put under".
• Few whole-body effects - Avoiding general IV medications decreases risks like breathing suppression or blood pressure drops.
• Excellent pain control - Numerous studies validate axillary blocks provide exceptional, prolonged pain relief in the affected arm.
• Faster recovery - Patients tend to have fewer issues with post-op nausea or headaches.

These benefits make axillary nerve blocks an excellent option alongside general anesthesia for surgeries like bone repairs after fractures. The blocks provide significant pain control both during and for the many hours immediately after surgery when healing starts.

Side Effects and Risks

All medical procedures carry some risks, but axillary nerve blocks are considered extremely safe overall. Still it's important to be aware of the short and long term side effects that may possibly develop.

Common Temporary Side Effects

Short term issues from axillary blocks may consist of:

• Numb or weak arm lasting many hours
• Bruise, swelling, or infection at injection site
• Headache, dizziness, nausea, or tinnitus
• Allergic reaction in susceptible patients

These frequently resolve on their own as the anesthetic wears off over 6-24 hours. But call your doctor if any worrisome or persistent symptoms arise.

Rare Long Term Nerve Damage Risk

Permanent injury to the axillary nerve or nearby nerves in the arm/shoulder is very rare. However estimated rates of longer lasting nerve problems may occur in:

• 1 in 200 to 1 in 1000 cases (0.05% - 0.1%) with axillary nerve blocks
• 1 in 5000 to 1 in 30000 cases (0.003% - 0.02%) after general anesthesia

So while still unlikely, nerve injury appears slightly more likely with blocks versus general anesthesia. Using ultrasound guidance during injection reduces this risk further.

Recovering After an Axillary Nerve Block

If an axillary nerve block was placed for surgery, you'll remain at the surgery center for 1-3 hours to ensure adequate stability as the anesthetic wears off.

During the day after surgery you must take care not to injure the numbed arm before full sensation returns. Avoid hot temperatures or sharp objects near the anesthetized region as well.

Your physician will provide instructions on wound care, watching for signs of infection, pain medication use, and follow up appointments needed. This helps ensure you recover smoothly in the days/weeks after surgery aided by the temporary nerve block.

The Takeaway

Axillary nerve blocks play an important role for certain arm surgeries and managing acute pain flare ups. Though the numbness feels very odd, the technique offers significant advantages over relying solely on general anesthesia or strong oral pain pills alone.

By understanding the axillary nerve pathway, reasons for blocking it, details of the injection procedure itself, typical effects, and aftercare, patients can obtain maximum benefit from this safe regional anesthesia method.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.