Peripheral nerve blocks (PNBs) are an important component in multimodal strategies for acute pain management. PNBs can be used as a sole anesthetic modality or as an adjunct to neuraxial or general anesthesia. The use of regional anesthesia confers many well documented clinical benefits. The wide availability of point-of-care ultrasound in clinical practice and the ubiquitous use of rapid recovery protocols increased the indications and utility of PNBs. A number of new regional anesthesia techniques have been introduced to facilitate early mobilization after surgery. The newer techniques tend to target specific distal sensory branches to decrease motor blockade. As an example, several truncal fascial plane blocks have been proposed as an alternative to epidural analgesia to avoid unwanted effects after thoracic and abdominal procedures (e.g., postural hypotension, motor weakness).
The proper choice of nerve blocks for specific procedures is essential for success. This chapter aims to provide guidance in decision-making for common clinical indications. Contraindications to PNBs are discussed in Table 7-1. Perioperative management protocols for patients having orthopedic surgical procedures are listed as an example for clinical context.
Table Graphic Jump Location TABLE 7-1Contraindications to Peripheral Nerve Blocks ||Download (.pdf) TABLE 7-1 Contraindications to Peripheral Nerve Blocks
|ABSOLUTE ||RELATIVE |
|Patient refusal ||Uncooperative or agitated patient |
|Documented allergy to multiple local anesthetics ||Vague history of allergy to local anesthetic (typically dental procedure) |
|Nerve/plexus trauma or evolving neuropathy ||History of neurologic deficits along the block distribution |
|Coagulopathy with deep blocks, especially blocks close to the neuraxis ||Coagulopathy or use of anticoagulants for peripheral perivascular blocks |
|Infection at the site of injection || |
UPPER EXTREMITY BLOCKS
Regional anesthesia can be used as the main anesthesia and analgesia modality for many surgical procedures on the upper extremity because the brachial plexus innervates the entire upper extremity. The level (proximal-distal) at which the brachial plexus is blocked can be tailored to the specific surgeries from the cervical roots to the distal peripheral nerves. Table 7-2 lists common nerve block procedures and their indications.
Table Graphic Jump Location TABLE 7-2Common Upper Extremity Blocks and Their Indications ||Download (.pdf) TABLE 7-2 Common Upper Extremity Blocks and Their Indications
|PERIPHERAL NERVE BLOCK ||INDICATIONS ||ADVANTAGES ||DISADVANTAGES |
|Interscalene brachial plexus block || || || |
Hemidiaphragmatic paralysis due to spread toward the phrenic nerve
Complex plexus architecture carries a higher risk of transient neuropathies compared to more distal blocks
Spares the lower trunk, therefore not recommended for surgery at the elbow and below
Side effects: Horner syndrome, recurrent laryngeal nerve block
|Supraclavicular brachial plexus block || |
Shoulder surgery (if the upper trunk is blocked)
Surgery of the arm, forearm, and hand