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Local and regional anesthesia

Last updated: August 27, 2020


Local and regional anesthesia, in contrast to systemic, general anesthesia, involves the reversible numbing of a specific region of the body to prevent any sensation of pain. Pain may be blocked on different levels of its signal transduction pathway, e.g., at the site of origin, along the nerves, or in the brain. Accordingly, local and regional anesthesia can be divided into local topical and infiltration anesthesia, regional peripheral nerve blocks (PNB), and neuraxial anesthesia (e.g., spinal and epidural). Local anesthesia can be combined with general anesthesia, allowing the doses of anesthetic and analgesic drugs to be reduced during surgery, and may eliminate the need for other measures to achieve sufficient anesthesia (depending on the timeframe of surgery, risk profile, patient's consent). In general, local anesthesia carries less risk than general anesthesia, as essential body functions (e.g., respiration) are not affected. However, specific complications (e.g., bleeding, infection) and contraindications (e.g., patient's refusal, allergies) to local anesthesia must be considered. The drugs used for anesthesia can be found in the article local anesthetic agents.


Local and regional anesthesia are used prior to certain medical procedures to reduce pain; see “Indications” in local anesthetic agents.


Local anesthesia

  • Definition: : Local anesthesia reversibly blocks nerve endings and pain conduction near the site of administration (limited area).
  • Indications: See local anesthetic agents.
  • Procedure
    • Topical anesthesia: application of gels, ointments, sprays, or patches anesthetic agent gets absorbed through the skin or mucosa
    • Infiltration anesthesia: injection of local anesthetic directly into a painful area or one to be operated on
      • Technique:
        • Hygiene is crucial and depends on the specific intervention!
        • Sufficient infiltration of the target area (e.g., wound margins of a cut) by injecting the local anesthetic drug from all sides with as few punctures as possible (avoid vascular infiltration by aspirating before injecting!)
      • Injection site: injected locally subcutaneously and/or submucosally wherever required (e.g., wound margins of a cut)

The effect of local anesthetic drugs is very limited in inflamed tissues (e.g., abscess)! The acidic environment of inflamed tissues leads to protonation of the anesthetic drug, which in turn reduces its lipophilicity and prevents the spread of the drug to the site of action.


Peripheral nerve block


  • Local anesthetic is injected near a specific nerve or nerve bundle.


  • Surgery of the upper extremities
  • Surgery of the lower extremities
  • Surgery of the scalp, neck, and trunk
  • Block of selected peripheral nerves (e.g., digital nerve block): technique to anesthetize the digits to perform surgery on the fingers or toes.

Relative contraindication


  • Injection site: depends on the nerves that need to be blocked
  • Technique
    1. Identification of the relevant nerve guided by specific landmarks and/or:
    2. Two approaches to inject the local anesthetic drugs are available:
      1. Single-shot technique: A single dose of the local anesthetic drug is injected (e.g., bupivacaine).
      2. Catheter placement with the advantage of repeated/continuous administration of anesthetic drugs

Peripheral nerve blocks are preferred over general anesthesia in patients with respiratory problems and preferred over epidural/spinal anesthesia in patients who are at high risk for urinary retention or other side effects of these procedures.


Epidural anesthesia





  • Injection site
  • Approaches to inject the local anesthetic:
    1. Catheter placement, which has the advantage of repeated/continuous administration of anesthetic drugs (most commonly performed)
    2. Single-shot technique



Spinal anesthesia



Used for a variety of lower extremity, lower abdominal, pelvic, and perineal procedures (e.g., cesarean delivery, hip and knee replacement)



  • Injection site
  • Approach: almost always single-shot technique



All procedures

Epidural/spinal anesthesia


We list the most important complications. The selection is not exhaustive.


  1. Jenkins B, McInnis M, Lewis C. Step-Up to USMLE Step 2 CK. Lippincott Williams & Wilkins ; 2015
  2. Chawla J. Epidural Nerve Block. Epidural Nerve Block. New York, NY: WebMD. http://emedicine.medscape.com/article/149646-overview. Updated: September 4, 2015. Accessed: February 20, 2017.
  3. Falk SA, Fleisher LA. Overview of anesthesia and anesthetic choices. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/overview-of-anesthesia-and-anesthetic-choices?source=machineLearning&search=epidural%20anesthesia&selectedTitle=1~150§ionRank=1&anchor=H13#H12.Last updated: July 22, 2016. Accessed: February 20, 2017.
  4. Gmyrek R. Local and Regional Anesthesia. Local and Regional Anesthesia. New York, NY: WebMD. http://emedicine.medscape.com/article/1831870-overview. Updated: July 7, 2015. Accessed: February 20, 2017.
  5. Turnbull DK, Shepherd DB. Post-dural puncture headache: pathogenesis, prevention and treatment. Br J Anaesth. 2003; 91 (5): p.718-729. doi: 10.1093/bja/aeg231 . | Open in Read by QxMD
  6. Sun-Edelstein C, Lay CL. Post-lumbar puncture headache. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/post-lumbar-puncture-headache?source=see_link.Last updated: August 17, 2016. Accessed: February 20, 2017.
  7. Clinical Relevance of the Bezold–Jarisch Reflex. http://anesthesiology.pubs.asahq.org/article.aspx?articleid=1943118. Updated: May 1, 2003. Accessed: February 20, 2017.
  8. Le T, Bhushan V, Sochat M, Petersen M, Micevic G, Kallianos K. First Aid for the USMLE Step 1 2014. McGraw-Hill Medical ; 2014
  9. Press CD. Topical Anesthesia. Topical Anesthesia. New York, NY: WebMD. http://reference.medscape.com/article/109673-overview. Updated: November 5, 2015. Accessed: February 20, 2017.
  10. Jeng CL, Rosenblatt MA. Overview of peripheral nerve blocks. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/overview-of-peripheral-nerve-blocks?source=search_result&search=peripheral%20nerve%20block&selectedTitle=1~126.Last updated: February 1, 2017. Accessed: February 20, 2017.
  11. Le T, Bhushan V, Chen V, King M. First Aid for the USMLE Step 2 CK. McGraw-Hill Education ; 2015
  12. Grant GJ, Hepner DL, Crowley M. Adverse Effects of Neuraxial Analgesia and Anesthesia for Obstetrics. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/adverse-effects-of-neuraxial-analgesia-and-anesthesia-for-obstetrics.Last updated: June 28, 2017. Accessed: October 7, 2017.
  13. Ituk U, Wong CA. Epidural and Combined Spinal-epidural Anesthesia: Techniques. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/epidural-and-combined-spinal-epidural-anesthesia-techniques.Last updated: July 25, 2017. Accessed: January 24, 2018.
  14. Gimeno AM, Errando CL. Neuraxial regional anaesthesia in patients with active infection and sepsis: a clinical narrative review. Turk J Anaesthesiol Reanim. 2018; 46 (1): p.8-14. doi: 10.5152/TJAR.2018.12979 . | Open in Read by QxMD
  15. Press CD. Subarachnoid Spinal Block. Subarachnoid Spinal Block. New York, NY: WebMD. http://emedicine.medscape.com/article/2000841-overview. Updated: November 30, 2015. Accessed: February 20, 2017.
  16. Agabegi SS, Agabegi ED. Step-Up To Medicine. Wolters Kluwer Health ; 2015