Nerve blocks are used for pain treatment and management. There are several different types of nerve blocks that fulfill different purposes.
A group of nerves, called a plexus or ganglion, that cause pain to a specific organ or region can be blocked with the injection of medication into a specific area of the body. The injection of this nerve-numbing substance is called a nerve block.
A nerve block is the interruption of signals traveling along a nerve for the purpose of pain relief. A local anesthetic injection is a short-term block, usually lasting hours or days, involving the injection of an anesthetic and other drugs such as steroids onto or near a nerve.
Nerve blocks are sterile procedures that can be performed with the help of ultrasound, fluoroscopy (a live X-ray) or CT to allow a better view of the placement of the needle. A probe positioning system can also be used to hold the ultrasound transducer steady. In addition, electrical stimulation can provide feedback on the proximity of the needle to the target nerve.
Peripheral Blocks & Local Anesthetic Injections
Peripheral nerve blocks play an important role in the anesthetic plan for patients undergoing many types of surgical procedures.
A peripheral nerve block is accomplished by injecting a local anesthetic near the nerve, or nerves, that control sensation and movement to a specific part of the body.
This injection will temporarily numb the area in question, resulting in a number of benefits.
Peripheral nerve blocks significantly reduce the risk of post-operative fatigue and confusion, dramatically reduce post-operative nausea and vomiting. The use of peripheral blocks, compared to central blocks, restrict the numbed area to the specific site of the surgery, or to one extremity, instead of numbing both legs, for example.
They offer better post-operative pain control and limit the need for strong pain medications, which can have complications, earlier discharge and improved patient satisfaction. Patients who have had peripheral nerve blocks tend to recover more quickly from surgery.
Nerve Block Types
The supra orbital branch of the trigeminal nerve lies just behind your eyes. The nerve’s three facial branches travel to the entire front half of your head. When the nerves are irritated, they produce pain symptoms that can travel along the nerve path.
These nerves can be irritated by muscle spasm, trigeminal neuralgia, TMJ and more. When irritated, the trigeminal nerve can create a severe pain signal, that may feel like a stabbing (intermittent or constant) headache; usually felt in front of the ears, behind the eyes or to the frontal forehead.
The supraorbital nerve block is often used to calm the nerves of the face, typically in the forehead. In order to diminish or resolve the resulting headaches, a nerve block will stop this signal.
A selective nerve root block (SNRB) is an injection of a local anesthetic along a specific nerve root. Along the spine, the nerve roots emerge from are several “holes.” If these holes (or foramina) are partially closed from bulging disks, bone spurs, misalignment of vertebrae, etc., the nerve root can also be pinched. This typically causes a shooting or radiating pain along the nerve root. In a selective nerve root block, a small needle is placed in the foramen alongside the nerve root and the medication is injected.
A SNRB is also known as selective transforaminal epidural injection with imaging guidance (fluoroscopy or CT).
The local anesthetic can reduce reduce pain and other symptoms, and it may provide diagnostic information relating to the cause of the pain.
A celiac plexus block is common for treating abdominal pain and is especially effective for pancreatic cancer pain and associated metastasis and it’s used to treat intractable pain from upper abdominal cancers.
The celiac plexus is a bundle of nerves located in front of the diaphragm and behind the stomach near the celiac artery and the abdominal aorta. The celiac plexus innervates the liver, pancreas, gallbladder, stomach, spleen, kidneys, intestines, adrenal glands, and blood vessels. Blocking this region can relieve pain caused by one of these organs.
The stellate ganglion is a collection of nerves located in the last vertebra of the neck. The nerves are found in front of the vertebrae and they are part of the sympathetic nervous system that reaches the face and arm. Sometimes, after a nerve is sensitized by trauma, infection or other causes, the sympathetic activity can cause pain, although the nerves are not part of feeling or movement.
Blocking the sympathetic activity by an injection of local anesthetic into the front of the neck on either side of the voicebox may help alleviate the pain.
A stellate ganglion block is conducted to:
Diagnose the cause of pain in the face and head, arms and chest
Manage pain in the head, neck, chest or arm caused by nerve injuries, the effects of an attack of shingles (herpes zoster) or angina that doesn’t go away
Reduce sweating in the face, head, arms and hands
Reduce pain, swelling, color and sweating changes in the upper extremities and may improve mobility
Treat reflex sympathetic dystrophy, sympathetic maintained pain or complex regional pain syndrome
As part of the treatment of Reflex Sympathetic Dystrophy (RSD)
A stellate ganglion block can be either diagnostic, to find the cause of a patient’s pain or therapeutic, to relieve the pain.
Superior hypogastric plexus blocks are used to control pelvic pain in patients with minimal relief from oral medications or who cannot tolerate the side-effects from oral medication, such as nausea, constipation, and sedation. The block can help with pain in any of these regions: the descending colon, rectum, testes, penis, prostate, perineum, vulva vagina, uterus, urethra and bladder. It can also help with pain secondary to endometriosis, radiation injury and cancers that metastasize to the pelvis.
Although every patient will experience a different degree of relief, the benefits of superior hypogastric plexus blocks can range from weeks to several years. It is a low risk, non-surgical treatment. If it is successful the first time, the tendency is for continual relief with multiple treatments and the amount of oral medications needed is reduced. The procedure has also shown to be very helpful in conjunction with other nerve blocks, such as the ganglion impar block.
Lumbar sympathetic block is an injection of local anesthetic in the “sympathetic nerve tissue” – the nerves that are a part of sympathetic nervous system. The nerves are located in the lower back, on either side of the spine. A lumbar sympathetic block is commonly administered if you are experiencing pain or poor circulation in your legs.
Normally these nerves control basic functions such as regulating blood flow. In certain conditions, these sympathetic nerves can carry pain information from the peripheral tissues back to the spinal cord. A lumbar sympathetic block is performed to obstruct the sympathetic nerves that go to the leg on the same side as the injection. This may in turn reduce pain, swelling, color, sweating and other unusual changes in the lower extremity and may improve mobility. The procedure is a part of the treatment of Reflex Sympathetic Dystrophy (RSD), Sympathetic Maintained Pain, Complex Regional Pain Syndrome and Herpes Zoster (shingles) involving the legs. Certain patients with neuropathy or peripheral vascular disease may also benefit from lumbar sympathetic blocks.
Trigger point injection is used to treat painful areas of muscle that contain trigger points, or knots of muscle that form when muscles do not relax. The knots can often be felt under the skin. Trigger points may irritate the nerves around them and cause pain that is felt in another part of the body.
With the injection, the trigger point is made inactive and the pain is alleviated. Usually, a brief course of treatment will result in sustained relief. Injections usually take just a few minutes and several sites may be injected in one visit.
In addition to trigger point injections, various modalities for the treatment of trigger points include spray and stretch, ultrasound and manipulative therapy.
Trigger point injections may provide relief of symptoms from myofascial pain syndrome. Myofascial pain syndrome is a common painful muscle disorder characterized by myofascial trigger points. It is distinguishable from fibromyalgia syndrome, which involves multiple tender points, although these pain syndromes may be concurrent. Myofascial trigger points often occur with chronic musculoskeletal pain disorders.
Not all trigger points require injection or needling. Many active trigger points will respond to physical therapy, especially in the early stages of trigger point formation. However, for chronic trigger points, trigger point injection and needling is an effective treatment for some patients.
Carpal tunnel syndrome (CTS) compresses the median nerve at the wrist because the transverse carpal ligament has become contracted as a result of physical activities, aging or both. Patients with CTS typically experience muscle weakness, tingling and numbness, particularly at night.
Carpal tunnel syndrome can be mild, moderate or severe. Mild CTS often causes intermittent numbness. In moderate CTS, the symptoms cause frequent nighttime wakening due to numbness pain. In severe CTS, decreased grip and pinch strength may result in loss of dexterity and thenar muscle atrophy may develop. Pain and paresthesias may radiate to the forearm, elbow and shoulder. Although one hand typically has more severe symptoms, both hands often are affected.
Ultrasonography of the carpal tunnel has been used to diagnose CTS and to identify causes of the condition, such as flexor tenosynovitis or a foreign body within the carpal tunnel, either of which may cause CTS.
Endoscopic carpal tunnel release surgery helps relieve the pain and numbness caused by carpal tunnel syndrome. Because it is minimally invasive, the incision is much smaller and recovery time is faster and less painful. There is less scar tissue for better cosmetic results. Endoscopic patients usually require less occupational therapy and can return to normal activities faster.
The endoscopic procedure offers symptom relief by by releasing the tight ligament over the median nerve. It is this compression on the median nerve that leads to the characteristic ‘pins and needles’ paresthesia in the thumb, index, long and ring fingers. Traditional “open” carpal tunnel surgery requires a large incision on the palm, which can be quite painful. The endoscopic method offers less dissection and interruption of tissue planes than the open methods because the endoscopic methods do not divide the subcutaneous tissues or the palmar fascia to the same degree as the open method does.
The procedure is conducted in-office, which means the patient goes home the same day. Most patients can resume light activities within days after the surgery; however, strong grip strength can take 4 – 6 weeks to return.