During the past 20 years, increasing knowledge in functional regional anesthesia anatomy, coupled with new technologies for locating peripheral nerves, has resulted in expansion of regional anesthesia techniques. This phenomenon served to provide the clinician with a wide variety of techniques from which to choose. Nevertheless, many nerve block techniques are quite similar and result in a similar, if not exact, distribution of anesthesia. The proper choice of the nerve block for a particular surgical procedure and/or patient, however, is far more important than deliberation on the minutia of various technical techniques. In this chapter, a rational selection of the nerve block techniques is approached in three sections. In the first section, indications for common nerve blocks are listed with a short summary of the advantages and disadvantages of each technique selected. In the second section, specific protocols for intraoperative anesthesia and postoperative analgesia for the common surgical procedures are suggested as practiced by anesthesiologists affiliated with the St. Luke's and Roosevelt Hospitals in New York. This cookbook approach was chosen to allow clinicians to duplicate the results that we have found, via trial and error, to work best in our own practice. The last section is a more comprehensive compendium of published medical literature on the indications for peripheral nerve blocks.
With the advent of ultrasound guidance for nerve blocks, the choice of which brachial plexus block to perform has become less relevant because the block can be extended by needle repositioning into the desired area. For example, the interscalene approach was not recommended in the past for procedures on the hand or elbow because it was believed that local anesthetic would not sufficiently cover the inferior trunk of the brachial plexus. However, this barrier can be overcome with the use of a low-interscalene approach or by using sonographic guidance to target all three trunks. Multiple injections at different levels of the brachial plexus through a single-needle insertion site can make the interscalene brachial plexus applicable for most upper limb procedures. Regardless, the common approaches to brachial plexus block are sufficiently different in their anesthetic coverage to deserve knowledgeable consideration when making a decision about which block to use. In addition to the anesthetic coverage, the block selection should also take into consideration other factors, such as patient comfort, preexisting respiratory dysfunction, and practitioner experience. Table 6-1 lists common nerve block procedures and their indications.
Table 6-1 Common Upper Limb Blocks ||Download (.pdf)
Table 6-1 Common Upper Limb Blocks
|PERIPHERAL NERVE BLOCK||INDICATIONS||ADVANTAGES||DISADVANTAGES|
|Interscalene brachial plexus block|
- Shoulder surgery
- Any surgery on the arm and humerus
- Manipulation of a frozen shoulder
- Also results in anesthesia of supraclavicular nerves
- Superficial, easy to perform, and comfortable for patient
- Hemidiaphragmatic paralysis
- Unless certain of inferior trunk blockade (by using US or a low-interscalene approach), not recommended for elbow, forearm, hand surgery
|Supraclavicular brachial plexus block|