Nerve block or regional nerve blockade is any deliberate interruption of signals traveling along a nerve, often for the purpose of

pain relief Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professional ...

Local anesthetic nerve block Local anesthetic nerve block (local anesthetic regional nerve blockade, or often simply nerve block) is a short-term nerve block involving the injection of local anesthetic as close to the nerve as possible for pain relief. The local anesthetic ...

(sometimes referred to as simply "nerve block") is a short-term block, usually lasting hours or days, involving the injection of an anesthetic, a

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are inv ...

, and other agents onto or near a nerve. Neurolytic block, the deliberate temporary degeneration of nerve fibers through the application of chemicals, heat, or freezing, produces a block that may persist for weeks, months, or indefinitely.

Neurectomy A neurectomy is a type of nerve block involving the severing or removal of a nerve. This surgery is performed in rare cases of severe chronic pain where no other treatments have been successful, and for other conditions such as vertigo, involuntary ...

, the cutting through or removal of a nerve or a section of a nerve, usually produces a permanent block. Because neurectomy of a

sensory nerve A sensory nerve, or afferent nerve, is a general anatomic term for a nerve which contains predominantly somatic afferent nerve fibers. Afferent nerve fibers in a sensory nerve carry sensory information toward the central nervous system (CNS) fro ...

is often followed, months later, by the emergence of new, more intense pain, sensory nerve neurectomy is rarely performed. The concept of nerve block sometimes includes ''central nerve block'', which includes

epidural Epidural administration (from Ancient Greek ἐπί, , upon" + ''dura mater'') is a method of medication administration in which a medicine is injected into the epidural space around the spinal cord. The epidural route is used by physicians an ...

and

spinal anaesthesia Spinal anaesthesia (or spinal anesthesia), also called spinal block, subarachnoid block, intradural block and intrathecal block, is a form of neuraxial regional anaesthesia involving the injection of a local anaesthetic or opioid into the suba ...

Local anesthetic nerve block

Local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...

is often combined with other drugs to potentiate or prolong the analgesia produced by the nerve block. These adjuvants may include

epinephrine Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and ...

corticosteroids Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invol ...

opioids Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid u ...

ketamine Ketamine is a dissociative anesthetic used medically for induction and maintenance of anesthesia. It is also used as a recreational drug. It is one of the safest anesthetics, as, in contrast with opiates, ether, and propofol, it suppress ...

, or

alpha-adrenergic agonist The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta ...

s. These blocks can be either single treatments, multiple injections over a period of time, or continuous infusions. A continuous peripheral nerve block can be introduced into a limb undergoing surgery – for example, a

femoral nerve block A femoral nerve block is a nerve block that uses local anesthetic to achieve analgesia in the leg. The block works by affecting the femoral nerve. A femoral nerve block (FNB) results in anesthesia of the skin and muscles of the anterior thigh an ...

to prevent pain in

knee replacement Knee replacement, also known as knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability, most commonly offered when joint pain is not diminished by conservative sources ...

. Local anesthetic nerve blocks are sterile procedures that are usually performed in an

outpatient A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health care ...

facility or hospital. The procedure can be performed with the help of

ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...

fluoroscopy Fluoroscopy () is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object. In its primary application of medical imaging, a fluoroscope () allows a physician to see the internal structure and function ...

, or CT to guide the practitioner in the placement of the needle. A probe positioning system can be used to hold the

ultrasound transducer Ultrasonic transducers and ultrasonic sensors are devices that generate or sense ultrasound energy. They can be divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasoun ...

steady. Electrical stimulation can provide feedback on the proximity of the needle to the target nerve. Historically, nerve blocks were performed blind or with electrical stimulation alone, but in contemporary practice, ultrasound or ultrasound with electrical stimulation is most commonly used. It is unclear if the use of

in addition to lidocaine is safe for nerve blocks of fingers and toes due to insufficient evidence. Another 2015 review states that it is safe in those who are otherwise healthy. The addition of dexamethasone to a nerve block or if given intravenously for surgery can prolong the duration of an upper limb nerve block leading to reduction in postoperative opioid consumption. Complications of nerve blocks most commonly include infection, bleeding, and block failure. Nerve injury is a rare side effect occurring roughly 0.03-0.2% of the time. The most significant complication of nerve blocks is local anesthetic systemic toxicity (LAST) which can include neurologic and cardiovascular symptoms including cardiovascular collapse and death. Other side effects can result from the specific medications used; for example, transient tachycardia may result if epinephrine is administered in the block. It is important to note that despite these complications, procedures done under regional anesthesia (nerve block with or without intravenous sedation) carry a lower anesthetic risk than general anesthesia.

Neurolytic block

A neurolytic block is a form of nerve block involving the deliberate injury of a nerve by freezing or heating ("

neurotomy Neurotomy may refer to the application of heat (as in radio frequency nerve lesioning) or freezing to sensory nerve fibers to cause their temporary degeneration, usually to relieve pain. Neurotomy and neurolysis (where the degeneration is caused by ...

") or the application of chemicals ("

neurolysis Neurolysis is the application of physical or chemical agents to a nerve in order to cause a temporary degeneration of targeted nerve fibers. When the nerve fibers degenerate, it causes an interruption in the transmission of nerve signals. In the med ...

"). These interventions cause degeneration of the nerve's fibers and temporary (a few months, usually) interference with the transmission of nerve signals. In these procedures, the thin protective layer around the nerve fiber, the

basal lamina The basal lamina is a layer of extracellular matrix secreted by the epithelial cells, on which the epithelium sits. It is often incorrectly referred to as the basement membrane, though it does constitute a portion of the basement membrane. The bas ...

, is preserved so that, as a damaged fiber regrows, it travels within its basal lamina tube and connects with the correct loose end, and function may be restored. Surgical cutting of a nerve (

neurectomy A neurectomy is a type of nerve block involving the severing or removal of a nerve. This surgery is performed in rare cases of severe chronic pain where no other treatments have been successful, and for other conditions such as vertigo, involuntary ...

), severs these basal lamina tubes, and without them to channel the regrowing fibers to their lost connections, over time a painful

neuroma A neuroma (; plural: neuromata or neuromas) is a growth or tumor of nerve tissue. Neuromas tend to be benign (i.e. not cancerous); many nerve tumors, including those that are commonly malignant, are nowadays referred to by other terms. Neuro ...

deafferentation pain Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or or ...

may develop. This is why the neurolytic is usually preferred over the surgical block. The neurolytic block is sometimes used to temporarily reduce or eliminate pain in part of the body. Targets include * the

celiac plexus The celiac plexus, also known as the solar plexus because of its radiating nerve fibers, is a complex network of nerves located in the abdomen, near where the celiac trunk, superior mesenteric artery, and renal arteries branch from the abdomi ...

, most commonly for cancer of the gastrointestinal tract up to the transverse colon, and pancreatic cancer, but also for stomach cancer, gall bladder cancer, adrenal mass, common bile duct cancer, chronic pancreatitis and active intermittent

porphyria Porphyria is a group of liver disorders in which substances called porphyrins build up in the body, negatively affecting the skin or nervous system. The types that affect the nervous system are also known as acute porphyria, as symptoms are ...

* the

splanchnic nerve The splanchnic nerves are paired visceral nerves (nerves that contribute to the innervation of the internal organs), carrying fibers of the autonomic nervous system ( visceral efferent fibers) as well as sensory fibers from the organs ( visceral a ...

, for retroperitoneal pain, and similar conditions to those addressed by the celiac plexus block but, because of its higher rate of complications, used only if the celiac plexus block is not producing adequate relief * the hypogastric plexus, for cancer affecting the descending colon, sigmoid colon and rectum, as well as cancers of the bladder, prostatic urethra, prostate, seminal vesicles, testicles, uterus, ovary and vaginal fundus * the

ganglion impar The pelvic portion of each sympathetic trunk is situated in front of the sacrum, medial to the anterior sacral foramina. It consists of four or five small sacral ganglia, connected together by interganglionic cords, and continuous above with the ab ...

, for the perinium, vulva, anus, distal rectum, distal urethra, and distal third of the vagina * the

stellate ganglion The stellate ganglion (or cervicothoracic ganglion) is a sympathetic ganglion formed by the fusion of the inferior cervical ganglion and the first thoracic (superior thoracic sympathetic) ganglion, which exists in 80% of people. Sometimes, the seco ...

, usually for head and neck cancer, or sympathetically mediated arm and hand pain * the

triangle of auscultation The triangle of auscultation is a relative thinning of the musculature of the back, situated along the medial border of the scapula which allows for improved listening to the lungs. Boundaries It has the following boundaries: * medially, by th ...

for pain from

rib fracture A rib fracture is a break in a rib bone. This typically results in chest pain that is worse with inspiration. Bruising may occur at the site of the break. When several ribs are broken in several places a flail chest results. Potential complicatio ...

s and post

thoracotomy A thoracotomy is a surgical procedure to gain access into the pleural space of the chest. It is performed by surgeons (emergency physicians or paramedics under certain circumstances) to gain access to the thoracic organs, most commonly the hea ...

using a

rhomboid intercostal block The triangle of auscultation is a relative thinning of the musculature of the back, situated along the medial border of the scapula which allows for improved listening to the lungs. Boundaries It has the following boundaries: * medially, by the ...

* the

intercostal nerves The intercostal nerves are part of the somatic nervous system, and arise from the anterior rami of the thoracic spinal nerves from T1 to T11. The intercostal nerves are distributed chiefly to the thoracic pleura and abdominal peritoneum, and di ...

, which serve the skin of the chest and abdomen * and a dorsal root ganglion may be treated by targeting the root inside the

subarachnoid cavity In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in th ...

, most effective for pain in the chest or abdominal wall, but also used for other areas including arm/hand or leg/foot pain.

Neurectomy

Neurectomy is a

surgical Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

procedure in which a

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the ...

or section of a nerve is severed or removed. Cutting a sensory nerve severs its basal lamina tubes, and without them to channel the regrowing fibers to their lost connections, over time a painful

or deafferentation pain may develop. This is why the neurolytic is usually preferred over the surgical sensory nerve block. This surgery is performed in rare cases of severe

chronic pain Chronic pain is classified as pain that lasts longer than three to six months. In medicine, the distinction between acute and chronic pain is sometimes determined by the amount of time since onset. Two commonly used markers are pain that continue ...

where no other treatments have been successful, and for other conditions such as involuntary twitching and excessive blushing or sweating.McMahon, M. (2012, November 6). What is a Neurectomy? (O. Wallace, Ed.) Retrieved from wise GEEK: http://www.wisegeek.com/what-is-a-neurectomy.htm# A brief "rehearsal"

local anesthetic nerve block Local anesthetic nerve block (local anesthetic regional nerve blockade, or often simply nerve block) is a short-term nerve block involving the injection of local anesthetic as close to the nerve as possible for pain relief. The local anesthetic ...

is usually performed before the actual neurectomy to determine efficacy and detect side effects. The patient is typically under

general anesthetic General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds that induce a loss of consciousness in humans or loss of righting reflex in animals. Clinical definitions are also extended to include an induced com ...

during the neurectomy, which is performed by a

neurosurgeon Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and peri ...

References

External links

{{Authority control Regional anesthesia

Local anesthetic nerve block

Neurolytic block

Neurectomy

See also

References

External links