In addition to potent analgesia, regional anesthesia may lead to reductions in the stress response, systemic analgesic requirements, opioid-related side effects, general anesthesia requirements, and, possibly, the development of chronic postoperative pain.
Regional anesthetics must be administered in an area where standard anesthetic monitors, supplemental oxygen, and resuscitative medications and equipment are immediately available.
Local anesthetic may be deposited at any point along the brachial plexus, depending on the desired block effects: interscalene for shoulder and proximal humerus surgical procedures; and supraclavicular, infraclavicular, and axillary for surgeries distal to the mid-humerus.
A properly performed interscalene block almost invariably blocks the ipsilateral phrenic nerve, so careful consideration must be given to patients with severe pulmonary disease or preexisting contralateral phrenic nerve palsy.
Brachial plexus block at the level of the cords provides excellent anesthesia for procedures at or distal to the elbow. The upper arm and shoulder are not anesthetized with this approach. As with other brachial plexus blocks, the intercostobrachial nerve (T2 dermatome) is spared.
The axillary, musculocutaneous, and medial brachial cutaneous nerves branch from the brachial plexus proximal to where local anesthetic is deposited for an axillary brachial plexus block, and thus are usually spared.
Often it is necessary to anesthetize a single terminal nerve, either for minor surgical procedures with a limited field or as a supplement to an incomplete brachial plexus block. Terminal nerves may be anesthetized anywhere along their course, but the elbow and the wrist are the two most favored sites.
Intravenous regional anesthesia, also called a Bier block, can provide intense surgical anesthesia for relatively short (45–60 min) surgical procedures on an extremity.
A femoral nerve block alone will seldom provide adequate surgical anesthesia, but it is often used to provide postoperative analgesia for hip, thigh, knee, and ankle procedures.
Posterior lumbar plexus blocks are useful for surgical procedures involving areas innervated by the femoral, lateral femoral cutaneous, and obturator nerves. Complete anesthesia of the knee can be attained with a proximal sciatic nerve block.
Blockade of the sciatic nerve may occur anywhere along its course and is indicated for surgical procedures involving the hip, thigh, knee, lower leg, and foot.
Popliteal nerve blocks provide excellent coverage for foot and ankle surgery, while sparing much of the hamstring muscles, allowing lifting of the foot with knee flexion, thus facilitating ambulation. All sciatic nerve blocks fail to provide complete anesthesia for the cutaneous medial leg and ankle joint capsule, but when a saphenous (or femoral) block is added, complete anesthesia below the knee is provided.
A complete ankle block requires a series of five nerve blocks, but the process may be streamlined to minimize needle insertions. All five injections are required to anesthetize the entire foot; however, surgical procedures rarely require that all terminal nerves be blocked.
Intercostal blocks result in the highest blood levels of local anesthetic per local anesthetic dose injected of any nerve block procedure, and if multiple blocks ...