Incidence of Neurapraxia by Type of Nerve Block

Neurapraxia is a transient block in the conduction of impulses through a peripheral nerve, which results in temporary loss of motor, sensory, or mixed function without structural damage. Clinically, it presents as numbness, paresthesia, weakness, or paralysis in the distribution of the affected nerve, typically occurring shortly after regional anesthesia or surgery. Recovery is expected and is usually complete within days to weeks as conduction resumes. According to the Seddon classification, neurapraxia is the mildest form of nerve injury, defined by the absence of axonal degeneration. In the context of regional anesthesia, neurapraxia accounts for the majority of postoperative neurological symptoms (1). The reported incidence of neurapraxia ranges from 0.03% to 2.8%, reflecting variations in study design, follow-up, and the type of nerve block involved. 

Upper extremity nerve block techniques, particularly interscalene and supraclavicular brachial plexus blocks, demonstrate higher rates of neurapraxia. Prospective data from shoulder surgery patients indicate that rates of neurological symptoms consistent with neurapraxia that resolve without intervention approach 2% following interscalene block (2). This pattern likely reflects the compact organization of neural elements and limited space for anesthetic dispersion in these areas. Of note, supraclavicular blocks demonstrate slightly lower rates. Infraclavicular and axillary blocks are associated with lower incidences as well, often below 1%. This may be related to improved needle control and greater spatial separation of nerve structures in this region of the upper body. 

Lower extremity nerve blocks, including femoral, sciatic, and popliteal approaches, demonstrate lower incidence of neurapraxia overall compared to other types. Registry and observational data suggest incidences typically between 0.1% and 0.5%, with most cases resolving without sequelae (3). Continuous catheter techniques may increase the likelihood of transient nerve irritation due to prolonged exposure or mechanical factors, though persistent deficits are uncommon. Determining the cause of postoperative neurological symptoms is often challenging, as similar findings may result from the nerve block itself or from perioperative factors such as positioning, compression, and surgical manipulation 

Neuraxial anesthesia presents a distinct but related profile. Transient neurologic symptoms, such as radicular pain or dysesthesia, occur in approximately 1% to 3% of cases, depending on anesthetic choice and technique, with lidocaine historically associated with higher rates (1). These effects are generally attributed to nerve root irritation or localized anesthetic exposure within the spinal canal, rather than the focal peripheral nerve injury seen with peripheral nerve blocks. 

Large contemporary analyses indicate that clinically significant peripheral nerve injury following regional anesthesia is uncommon, occurring in fewer than 0.1% of cases. Most of these cases involve transient dysfunction rather than permanent damage (4). Differences in incidence of neurapraxia and neurological injury across nerve block types highlight the influence of anatomy, technique, and procedural context. In practice, these findings support risk stratification when selecting block approaches and reinforce the importance of ultrasound guidance, careful needle advancement, and avoiding high injection pressures. 

Neurapraxia is the most common neurological complication of nerve blocks, with incidence rates varying according to anatomical site and technique. Proximal upper extremity blocks carry relatively higher rates of transient symptoms, while distal and lower extremity approaches demonstrate a lower incidence rate. Despite this variation, outcomes are consistently favorable, supporting the continued use of regional anesthesia within a framework of careful technique and patient-specific risk assessment.

References 

1. Brull R, McCartney CJ, Chan VW, El-Beheiry H. Neurological complications after regional anesthesia: contemporary estimates of risk. Anesth Analg. 2007;104(4):965-974. doi:10.1213/01.ane.0000258740.17193.ec

2. Neal JM, Barrington MJ, Brull R, et al. The Second ASRA Practice Advisory on Neurologic Complications Associated With Regional Anesthesia and Pain Medicine: Executive Summary 2015. Reg Anesth Pain Med. 2015;40(5):401-430. doi:10.1097/AAP.0000000000000286

3. Barrington MJ, Watts SA, Gledhill SR, et al. Preliminary results of the Australasian Regional Anaesthesia Collaboration: a prospective audit of more than 7000 peripheral nerve and plexus blocks for neurologic and other complications. Reg Anesth Pain Med. 2009;34(6):534-541. doi:10.1097/aap.0b013e3181ae72e8

4. Luo T, Berecki-Gisolf J, Marshall S. Incidence of peri-operative peripheral nerve injuries associated with general and regional anaesthesia: an observational study. Anaesthesia. 2026;81(5):627-636. doi:10.1111/anae.70081