What is Peripheral Nerve Block?
Nerve Block involves injection of anesthetic medication and long lasting steroid ("cortisone") around a specific peripheral nerve that is involved in carrying the pain signal to the brain from a specific part of the body. In general, it involves doing something to a nerve that alters the way in which it is able to transmit painful signals-this is called a conduction block and is a form of neuromodulation. Nerve blocks can be short or long term depending on which technique is used.

What is the purpose of Peripheral Nerve Block?
The anesthetic medication injection numbs up the nerve for a certain length of time. The steroid medication injected reduces the inflammation and/or swelling of nerves. This may in turn reduce pain, tingling & numbness and other symptoms caused by nerve inflammation / irritation or swelling.

How long does the injection take?
The actual injection takes only a few minutes.

What is actually injected?
The injection consists of a mixture of local anesthetic (like Lidocaine or Bupivacaine) and the steroid medication (Triamcinolone – Aristocort® or Methylprednisolone – Depo-medrol®).

Will the injection hurt?
The procedure involves inserting a needle through skin and deeper tissues (like a "tetanus shot"). So, there is some discomfort involved. However, we numb the skin with ice pack or by spraying a local anesthetic spray when needed. These techniques makes the procedure easy to tolerate.

Will I be "put out" for this procedure?
No. This procedure is done under local anesthesia. Most of the patients tolerate the procedure easily.

How is the injection performed?
The skin overlying the peripheral nerve is cleaned with antiseptic, anesthetic spray is used to numb the skin and then the injection is carried out. The block is usually done somewhere between the source of the nerve injury and it's connection to the spinal cord.

What should I expect after the injection?
Immediately after the injection, you may feel numbness in the area of distribution of the nerve. Also, you may notice that your pain may be gone or quite less. This is due to the local anesthetic injected. This will last only for a few hours. You should start noticing pain relief starting the 3rd day or so.

What should I do after the procedure?
You use an ice pack or heating pad if you feel any soreness near the injection site. We advise the patients to take it easy for a day or so after the procedure. Perform the activities as tolerated by you.

Can I go back to work the next day?
You should be able to unless the procedure was complicated. Usually you will feel some back pain or have a "sore back" only.

How long is the effect of the medication last?
The immediate effect is usually from the local anesthetic injected. This wears off in a few hours. The cortisone starts working in about 3 to 5 days and its effect can last for several days to a few months.

How many injections do I need to have?
If the first injection does not relieve your symptoms in about a week to two weeks, you may be recommended to have one more injection. Similarly, if the second injection does not relieve your symptoms in about a week to two weeks, you may be recommended to have a third injection. When repeated several times, some patients notice significant reduction in their pain which outlasts the theoretical length of action of the local anesthetic. This may be due to some form of neuromodulation in the dorsal horn of the spinal cord.

Can I have more than three injections?
In a six month period, we generally do not perform more than three injections. This is because the medication injected lasts for about six months. If three injections have not helped you much, it is very unlikely that you will get nay further benefit from more injections. Also, giving more injections will increase the likelihood of side effects from cortisone.

Will the Peripheral Nerve Block help me?
It is very difficult to predict if the injection will indeed help you or not. Generally speaking, the patients who have "localized symptoms" respond better to the injections than the patients who have diffuse pain. Similarly, the patients with a recent onset of pain may respond much better than the ones with a long standing pain.

What are the risks and side effects?
Generally speaking, this procedure is safe. However, with any procedure there are risks, side effects, and possibility of complications. The most common side effect is pain – which is temporary. The other risk involve infection, bleeding, nerve damage, worsening of symptoms etc. The other risks are related to the side effects of cortisone: These include weight gain, increase in blood sugar (mainly in diabetics), water retention, suppression of body's own natural production of cortisone etc. These side effects are rare and depend on the number of injections and dosage of cortisone used.

Who should not have this injection?
If you are allergic to any of the medications to be injected, if you are on a blood thinning medication (e.g. Coumadin, Plavix), or if you have an active infection going on, you should not have the injection.

What are the different causes for which Peripheral Nerve Blocks are used?

• Peripheral Neuropathy - neuralgic pain caused by a number of disease processes / toxins which affect the function of different components of peripheral nerves.
• Entrapment Neuropathy - neuralgic pain caused by peripheral nerves being trapped by different anatomical structures in the body.
• Post Traumatic Neuropathy - neuralgic pain which comes on after trauma or surgery.
• Post Herpetic Neuralgia - neuralgia which arises due to damage to the peripheral and central nervous system by the herpes virus.
• Phantom Limb Pain - neuralgia which comes on following traumatic or surgical amputation of a limb.

What is Neurolytic Peripheral Nerve Block?

Neurolytic Block is a long term technique of Peripheral Nerve Block. This technique involves use of nerve destructive substances like Phenol or Absolute Alcohol injected directly to the nerves which supply the part of the body responsible for causing the pain. This technique is usually reserved for those patients with terminal conditions like cancer, and who are close to the end of their life.

What is Radiofrequency technique (RF)?