Superficial and deep nerve blocks are important techniques in regional anesthesia that provide targeted pain relief by interrupting nerve conduction at different anatomical levels. These blocks vary in depth, application, and associated risks, making them suitable for different surgical and pain management scenarios. Superficial nerve blocks are performed closer to the skin and target smaller peripheral nerves, whereas deep nerve blocks target larger nerves or nerve plexuses located within muscle compartments or deep fascial planes (1).
Superficial nerve blocks are used primarily for minor surgical procedures and postoperative pain management in the ambulatory setting. These blocks involve the deposition of a local anesthetic into superficial tissues, leading to a rapid onset of anesthesia with a relatively low risk of complications. Examples include the superficial cervical plexus block, commonly used for thyroid and carotid procedures, and the superficial radial nerve block, which provides analgesia for hand and wrist surgeries. Because the anesthetic remains in superficial layers, systemic absorption is usually limited, reducing the risk of toxicity. However, the duration of analgesia may be shorter than with deep nerve blocks, necessitating additional analgesic interventions if prolonged pain control is required (2).
Deep nerve blocks, on the other hand, are used for more extensive surgical procedures that require prolonged and deep analgesia. These blocks target major nerve trunks, such as the brachial plexus, lumbar plexus, or sciatic nerve. A common deep nerve block is the infraclavicular brachial plexus block, which is often used in upper extremity surgery to provide complete anesthesia of the arm. Similarly, the lumbar plexus block is useful for hip and lower extremity surgery, providing superior analgesia compared to general anesthesia alone. However, because these blocks are administered at greater depths, they carry an increased risk of complications, including nerve injury, intravascular injection, and pneumothorax, particularly in cases where anatomical variations make nerve localization more difficult (3).
The use of ultrasound guidance has significantly improved the safety and efficacy of both superficial and deep nerve blocks. By providing real-time visualization of anatomical structures, ultrasound guidance reduces the risk of inadvertent vascular or organ puncture and increases the precision of anesthetic delivery. Studies have shown that ultrasound-guided deep nerve blocks, such as femoral and sciatic nerve blocks, result in more consistent anesthesia with fewer complications compared to traditional landmark-based techniques. In addition, ultrasound guidance allows for the administration of lower doses of anesthetic while achieving equivalent or superior analgesic effects, thereby minimizing the risk of systemic toxicity (2).
Despite their effectiveness, both superficial and deep nerve blocks have limitations and contraindications. Superficial nerve blocks may be inadequate for procedures requiring extensive anesthesia, requiring adjunctive analgesia. Conversely, deep nerve blocks require greater technical expertise and carry higher risks, particularly in patients with coagulopathies or distorted anatomy due to prior surgery or trauma. Clinicians must carefully evaluate patient-specific factors, including comorbidities, anatomical considerations, and surgical requirements, before selecting the most appropriate nerve block technique (4).
Superficial and deep nerve blocks are essential components of multimodal pain management strategies and provide effective and targeted analgesia for a wide range of surgical procedures. The choice between these techniques should be based on the surgical context, patient safety, and clinician expertise. As advances in regional anesthesia continue, refinement of nerve block techniques, coupled with improved imaging modalities, will improve both efficacy and patient outcomes.
References
- 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
- Jeng CL, Torrillo TM, Rosenblatt MA. Complications of peripheral nerve blocks. Br J Anaesth. 2010;105 Suppl 1:i97-i107. doi:10.1093/bja/aeq273
- Brull R, Hadzic A, Reina MA, Barrington MJ. Pathophysiology and Etiology of Nerve Injury Following Peripheral Nerve Blockade [published correction appears in Reg Anesth Pain Med. 2024 May 7;49(5):e2. doi: 10.1136/AAP.0000000000000125corr1.]. Reg Anesth Pain Med. 2015;40(5):479-490. doi:10.1097/AAP.0000000000000125
- El-Boghdadly K, Albrecht E, Wolmarans M, et al. Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of upper and lower limb nerve blocks. Reg Anesth Pain Med. 2024;49(11):782-792. Published 2024 Nov 4. doi:10.1136/rapm-2023-104884