Peripheral Nerve Blocks
The peripheral nervous system carries signals of movement and sensations such as heat, cold and pain from different parts of your body to the central nervous system formed by the spinal cord and brain. Injecting an anesthetic around a peripheral nerve can block the transfer of pain signals from the region it supplies to the brain. This is called a peripheral nerve block and can be used to manage chronic pain.
A common peripheral nerve block is the celiac plexus block. The celiac plexus is a bundle of nerves around the aorta that carry pain impulses from various abdominal organs.
The greater occipital nerve is a peripheral nerve that travels through the muscles at the back of the head and into the scalp providing sensation to the back and top of the scalp. A greater occipital nerve block involves injecting medication around the greater occipital nerve to relieve pain.
A celiac plexus block is indicated to relieve chronic pain in the abdominal region, most often due to pancreatic cancer or pancreatitis.
Greater occipital nerve blocks are commonly used for patients with a unilateral headache, mainly at the back of the head. This block may also be used in patients with occipital neuralgia experiencing shooting, zapping, stinging, or burning pain in the back of the head. Patients with migraines, cluster headaches, and other painful conditions may also obtain temporary relief with this block.
A celiac plexus block is carried out under local anesthesia and sometimes sedation. You will lie on your stomach on an X-ray table and your blood pressure, oxygen and heart activity are monitored. The region of skin to be injected is cleansed with an antiseptic solution and local anesthesia is administered. X-ray images are taken to guide the needle to the correct position of the nerve plexus. A test dye is injected to ascertain the correct location. Then the anesthetic is injected gradually over a couple of minutes. Sometimes, the anesthetic is combined with a steroid to prolong pain relief, or alcohol or phenol to destroy damaged nerves. Once the medication has been injected completely, the needle is removed and a bandage is placed. The entire procedure takes about 10 to 30 minutes.
For an occipital nerve block, you will lie down on an examination table. Your doctor then locates the greater occipital nerve by palpation of the scalp. The skin is cleansed with alcohol and your doctor injects a local anesthetic and steroid mix with a fine needle over the area of the trunk of the nerve. The injected region becomes numb and pain is relieved.
After a celiac plexus block, you may feel warmth in your abdomen, and experience pain relief that will last for a few days. For a better outcome, you are advised to have a series of 2 to 10 injections at varying intervals. The duration of relief tends to get longer after each injection.
Following the occipital nerve block, the anesthetic effect wears off over several hours and the steroid begins to act over the next few days. This helps provide pain relief for several days to a few months.
Risks and complications
Although celiac plexus nerve block is a safe procedure, it may be associated with certain side effects and risks such as temporary pain and soreness at the injection site, temporary weakness or numbness near the abdominal wall or legs, bleeding, infection or injection of the anesthetic at other regions of the spine, blood vessels and surrounding tissues.
Risks and complications are rare following an occipital block but can include infection, nerve or blood vessel injury, and allergic reaction to medications. You may also feel dizzy for a short period. Sometimes, thinning of the scalp at the injection site and hair loss may also occur.