Nerve block

Nerve block
Nerve block
Intervention
ICD-9-CM 04.81
MeSH D009407

Regional nerve blockade, or more commonly nerve block, is a general term used to refer to the injection of local anesthetic onto or near nerves for temporary control of pain. It can also be used as a diagnostic tool to identify specific nerves as pain generators. Permanent nerve block can be produced by destruction of nerve tissue.

Contents

Therapeutic uses

Nerve blocks can help patients who suffer from lower back pain, neck pain, sciatica (from a herniated disc), spinal stenosis, reflex sympathetic dystrophy (a complex regional pain syndrome), shingles, cancer, and painful peripheral vascular disease. It can also be used in the treatment of migraine headaches.

Methods

Sonography guided femoral nerve block.

Temporary nerve blocks are achieved by combining a local anesthetic (such as lidocaine) with epinephrine, a steroid (corticosteroid), and/or opioids. Epinephrine produces constriction of the blood vessels which delays the diffusion of the anesthetic. Steroids can help to reduce inflammation. Opioids are painkillers. Injection nerve 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 to prevent pain in knee replacement.[1]

Permanent nerve block can be effected using other drugs or methods including alcohol or phenol to selectively destroy nerve tissue, cryoanalgesia to freeze nerves, and Radiofrequency ablation to destroy nerve tissue using heat.

Nerve blocks are sterile procedures that are usually performed in an outpatient facility or hospital. The procedure can be performed with the help of ultrasound, fluoroscopy (a live X-ray) or CT. Use of any one of these imaging modalities enables the physician to view the placement of the needle. A probe positioning system can 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.

Digital nerve block

Digital nerve blocks involve infiltrating local anesthesia around the two nerves that supply a digit. Historically this has been done with a local anesthetic without epinephrine however the use of a solution with epinephrine appears to be safe.[2]

Complications

Nerve blocks, like other medical procedures, are not risk-free. There is a possibility of side effects and complications from the procedure, needle puncture, and medications used. The most critical factor in the efficacy of a nerve block is the proper location of the target nerve.

Complications include:

  • Infection
  • Allergy reactions
  • Increased pain

In other animals

Short-term nerve blocks are useful in regionalizing the source of pain during lameness examinations in horses. A local anesthetic alone is injected perineurally to desensitize tissues beyond the site of injection. For example, the palmar digital nerves can be blocked to investigate pain arising from the sole and heel area of the hoof. If pain is arising from this area, the horse will stop limping. If the source of lameness arises from higher up in the leg, the horse will continue to limp, and a nerve block can be performed higher up the leg. Because there are essentially no motor neurons in the lower limbs of horses, the risk of weakness or ataxia is negligible.[3]

References

  1. ^ UCSD. Regional anesthesia
  2. ^ Chowdhry S, Seidenstricker L, Cooney DS, Hazani R, Wilhelmi BJ (December 2010). "Do not use epinephrine in digital blocks: myth or truth? Part II. A retrospective review of 1111 cases". Plast. Reconstr. Surg. 126 (6): 2031–4. doi:10.1097/PRS.0b013e3181f44486. PMID 20697319. 
  3. ^ Bassage II, Lance; Ross MW (2003). "Diagnostic Analgesia". In Ross MW, Dyson SJ. Diagnosis and Management of Lameness in the Horse. St. Louis, MO: Saunders. pp. 93–124. ISBN 0-7216-8342-8. 

External links


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Look at other dictionaries:

  • nerve block — n 1) an interruption of the passage of impulses through a nerve (as with pressure or narcotization) called also nerve blocking 2) BLOCK ANESTHESIA * * * a method of producing anaesthesia in part of the body by blocking the passage of pain… …   Medical dictionary

  • nerve block — n. a method of local anesthesia in which the passage of impulses through a particular nerve is stopped by the injection of an anesthetic into or near the nerve …   English World dictionary

  • nerve block — noun : an interruption of the passage of impulses through a nerve (as with pressure or narcotization); sometimes : block anesthesia * * * Med. an arrest of the passage of impulses through a nerve by means of pressure on the nerve or by injection… …   Useful english dictionary

  • nerve block anaesthesia — noun anesthesia of an area supplied by a nerve; produced by an anesthetic agent applied to the nerve • Syn: ↑conduction anesthesia, ↑conduction anaesthesia, ↑nerve block anesthesia, ↑block anesthesia, ↑block anaesthesia • Hypernyms: ↑anesthesia …   Useful english dictionary

  • nerve block anesthesia — noun anesthesia of an area supplied by a nerve; produced by an anesthetic agent applied to the nerve • Syn: ↑conduction anesthesia, ↑conduction anaesthesia, ↑nerve block anaesthesia, ↑block anesthesia, ↑block anaesthesia • Hypernyms: ↑anesthesia …   Useful english dictionary

  • nerve block — Med. an arrest of the passage of impulses through a nerve by means of pressure on the nerve or by injection of an anesthetic into or around the nerve. [1920 25] * * * …   Universalium

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  • block — 1. To obstruct; to arrest passage through. 2. A condition in which the passage of an electrical impulse is arrested, wholly or in part, temporarily or permanently. 3. SYN: atrioventricular b.. [Fr. bloquer] alveolocapillary b. the presence of… …   Medical dictionary

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